[Camping] [Multiplayer Only] Opening equipped backpack will kick player

[GraciousMaximus]

Minecraft Version

1.20.1

Mod

Camping

Mod Version

1.0.4 Fabric

Latest Version

• Yes. I'm using the latest Version.

Issue Description

When opening an equipped backpack in a multiplayer server, it will frequently kick the player. It does not crash the game nor server. It is not every time it's opened, making it technically usable, but it's often enough that it's extremely easy to recreate. Some players are being kicked every time they open their backpack. Luckily, it does not seem to alter the backpack contents, but it's still strange and annoying.
This cannot be recreated in singleplayer. Haven't been able to do a minimal instance test because of this, as it would require setting up an entire second instance of the server.

Steps to Reproduce

1. Be on a 1.20.1 multiplayer fabric server with Let's Do: Camping. This cannot be recreated in singleplayer, even with the same mod list.
2. Equip backpack into backpack slot. This cannot be recreated with a placed backpack.
3. Open backpack while it is equipped. This may take multiple tries.
4. Player is kicked from server. The given error is Internal Exception: java.util.ConcurrentModificationException

Logs

Here's the console log. It includes the entirety of me joining and getting kicked.

Here's our mod list, to examine for any known compat issues.

Here's a video clip of what the player sees. I did it multiple times, in order to show that it's inconsistent.

Minimal Instance Test

• Yes, I've tested on a minimal instance.

Check for Similar Issues

• Yes, I have checked for similar issues.

[ikak0]

i get the same issue on singleplayer, though i do have not enough crashes installed.
crash report is this:
[22:02:01] [Netty Server IO #1/ERROR]: Encountered exception while handling in channel with name "camping:open_backpack" java.util.ConcurrentModificationException: null at java.util.HashMap$HashIterator.nextNode(Unknown Source) ~[?:?] at java.util.HashMap$KeyIterator.next(Unknown Source) ~[?:?] at net.minecraft.class_4558.method_22510(class_4558.java:60) ~[client-intermediary.jar:?] at net.minecraft.class_2066.method_24362(class_2066.java:55) ~[client-intermediary.jar:?] at net.minecraft.class_2066.method_8950(class_2066.java:51) ~[client-intermediary.jar:?] at net.minecraft.class_3222$2.method_7635(class_3222.java:252) ~[client-intermediary.jar:?] at net.minecraft.class_1703.method_34246(class_1703.java:219) ~[client-intermediary.jar:?] at net.minecraft.class_1703.method_7623(class_1703.java:176) ~[client-intermediary.jar:?] at net.satisfy.camping.client.screen.BackpackScreenHandler.method_7623(BackpackScreenHandler.java:88) ~[letsdo-camping-fabric-1.0.4.jar:?] at net.minecraft.class_1703.method_7596(class_1703.java:139) ~[client-intermediary.jar:?] at net.minecraft.class_3222.method_14235(class_3222.java:430) ~[client-intermediary.jar:?] at net.minecraft.class_3222.method_17355(class_3222.java:1042) ~[client-intermediary.jar:?] at net.satisfy.camping.network.OpenBackpackPacket.handle(OpenBackpackPacket.java:65) ~[letsdo-camping-fabric-1.0.4.jar:?] at net.satisfy.camping.network.OpenBackpackPacket.lambda$register$1(OpenBackpackPacket.java:99) ~[letsdo-camping-fabric-1.0.4.jar:?] at dev.architectury.networking.fabric.NetworkManagerImpl.lambda$registerC2SReceiver$0(NetworkManagerImpl.java:80) ~[architectury-9.2.14-fabric.jar:?] at dev.architectury.networking.transformers.PacketTransformer$1.inbound(PacketTransformer.java:47) ~[architectury-9.2.14-fabric.jar:?] at dev.architectury.networking.fabric.NetworkManagerImpl.lambda$registerC2SReceiver$1(NetworkManagerImpl.java:75) ~[architectury-9.2.14-fabric.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.receive(ServerPlayNetworkAddon.java:85) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.receive(ServerPlayNetworkAddon.java:39) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.AbstractChanneledNetworkAddon.handle(AbstractChanneledNetworkAddon.java:101) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.handle(ServerPlayNetworkAddon.java:80) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.minecraft.class_3244.handler$fcj000$fabric-networking-api-v1$handleCustomPayloadReceivedAsync(class_3244.java:2004) ~[client-intermediary.jar:?] at net.minecraft.class_3244.method_12075(class_3244.java) ~[client-intermediary.jar:?] at net.minecraft.class_2817.method_12199(class_2817.java:38) ~[client-intermediary.jar:?] at net.minecraft.class_2817.method_11054(class_2817.java:7) ~[client-intermediary.jar:?] at net.minecraft.class_2535.method_10759(class_2535.java:175) ~[client-intermediary.jar:?] at net.minecraft.class_2535.method_10770(class_2535.java:160) ~[client-intermediary.jar:?] at net.minecraft.class_2535.channelRead0(class_2535.java:52) ~[client-intermediary.jar:?] at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:299) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.finishPeerRead0(LocalChannel.java:445) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.access$400(LocalChannel.java:50) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel$5.run(LocalChannel.java:403) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470) ~[netty-common-4.1.82.Final.jar:?] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.82.Final.jar:?] at java.lang.Thread.run(Unknown Source) ~[?:?] [22:02:01] [Netty Server IO #1/ERROR]: Exception occurred in netty pipeline java.util.ConcurrentModificationException: null at java.util.HashMap$HashIterator.nextNode(Unknown Source) ~[?:?] at java.util.HashMap$KeyIterator.next(Unknown Source) ~[?:?] at net.minecraft.class_4558.method_22510(class_4558.java:60) ~[client-intermediary.jar:?] at net.minecraft.class_2066.method_24362(class_2066.java:55) ~[client-intermediary.jar:?] at net.minecraft.class_2066.method_8950(class_2066.java:51) ~[client-intermediary.jar:?] at net.minecraft.class_3222$2.method_7635(class_3222.java:252) ~[client-intermediary.jar:?] at net.minecraft.class_1703.method_34246(class_1703.java:219) ~[client-intermediary.jar:?] at net.minecraft.class_1703.method_7623(class_1703.java:176) ~[client-intermediary.jar:?] at net.satisfy.camping.client.screen.BackpackScreenHandler.method_7623(BackpackScreenHandler.java:88) ~[letsdo-camping-fabric-1.0.4.jar:?] at net.minecraft.class_1703.method_7596(class_1703.java:139) ~[client-intermediary.jar:?] at net.minecraft.class_3222.method_14235(class_3222.java:430) ~[client-intermediary.jar:?] at net.minecraft.class_3222.method_17355(class_3222.java:1042) ~[client-intermediary.jar:?] at net.satisfy.camping.network.OpenBackpackPacket.handle(OpenBackpackPacket.java:65) ~[letsdo-camping-fabric-1.0.4.jar:?] at net.satisfy.camping.network.OpenBackpackPacket.lambda$register$1(OpenBackpackPacket.java:99) ~[letsdo-camping-fabric-1.0.4.jar:?] at dev.architectury.networking.fabric.NetworkManagerImpl.lambda$registerC2SReceiver$0(NetworkManagerImpl.java:80) ~[architectury-9.2.14-fabric.jar:?] at dev.architectury.networking.transformers.PacketTransformer$1.inbound(PacketTransformer.java:47) ~[architectury-9.2.14-fabric.jar:?] at dev.architectury.networking.fabric.NetworkManagerImpl.lambda$registerC2SReceiver$1(NetworkManagerImpl.java:75) ~[architectury-9.2.14-fabric.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.receive(ServerPlayNetworkAddon.java:85) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.receive(ServerPlayNetworkAddon.java:39) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.AbstractChanneledNetworkAddon.handle(AbstractChanneledNetworkAddon.java:101) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.fabricmc.fabric.impl.networking.server.ServerPlayNetworkAddon.handle(ServerPlayNetworkAddon.java:80) ~[fabric-networking-api-v1-1.3.12+13a40c6677-3b97aa93efa4c799.jar:?] at net.minecraft.class_3244.handler$fcj000$fabric-networking-api-v1$handleCustomPayloadReceivedAsync(class_3244.java:2004) ~[client-intermediary.jar:?] at net.minecraft.class_3244.method_12075(class_3244.java) ~[client-intermediary.jar:?] at net.minecraft.class_2817.method_12199(class_2817.java:38) ~[client-intermediary.jar:?] at net.minecraft.class_2817.method_11054(class_2817.java:7) ~[client-intermediary.jar:?] at net.minecraft.class_2535.method_10759(class_2535.java:175) ~[client-intermediary.jar:?] at net.minecraft.class_2535.method_10770(class_2535.java:160) ~[client-intermediary.jar:?] at net.minecraft.class_2535.channelRead0(class_2535.java:52) ~[client-intermediary.jar:?] at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.readInbound(LocalChannel.java:299) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.finishPeerRead0(LocalChannel.java:445) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel.access$400(LocalChannel.java:50) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.channel.local.LocalChannel$5.run(LocalChannel.java:403) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470) ~[netty-common-4.1.82.Final.jar:?] at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:569) ~[netty-transport-4.1.82.Final.jar:?] at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.82.Final.jar:?] at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.82.Final.jar:?] at java.lang.Thread.run(Unknown Source) ~[?:?]