diff --git a/src/main/java/fi/dy/masa/litematica/render/schematic/BufferBuilderCache.java b/src/main/java/fi/dy/masa/litematica/render/schematic/BufferBuilderCache.java
index fb3e8ceec1..9e392a0c6e 100644
--- a/src/main/java/fi/dy/masa/litematica/render/schematic/BufferBuilderCache.java
+++ b/src/main/java/fi/dy/masa/litematica/render/schematic/BufferBuilderCache.java
@@ -2,16 +2,14 @@
 
 import javax.annotation.Nonnull;
 import java.util.ArrayList;
-import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
-
 import net.minecraft.client.render.BuiltBuffer;
 import net.minecraft.client.render.RenderLayer;
 
 public class BufferBuilderCache implements AutoCloseable
 {
     private final ConcurrentHashMap<RenderLayer, BufferBuilderPatch> blockBufferBuilders = new ConcurrentHashMap<>();
-    private final Map<ChunkRendererSchematicVbo.OverlayRenderType, BufferBuilderPatch> overlayBufferBuilders = new ConcurrentHashMap<>();
+    private final ConcurrentHashMap<ChunkRendererSchematicVbo.OverlayRenderType, BufferBuilderPatch> overlayBufferBuilders = new ConcurrentHashMap<>();
 
     protected BufferBuilderCache() { }
 
@@ -32,26 +30,31 @@ protected BufferBuilderPatch getBufferByLayer(RenderLayer layer, @Nonnull Buffer
 
     protected BufferBuilderPatch getBufferByOverlay(ChunkRendererSchematicVbo.OverlayRenderType type, @Nonnull BufferAllocatorCache allocators)
     {
-        return overlayBufferBuilders.computeIfAbsent(type,(key) -> new BufferBuilderPatch(allocators.getBufferByOverlay(key), key.getDrawMode(), key.getVertexFormat()));
+        return overlayBufferBuilders.computeIfAbsent(type, (key) -> new BufferBuilderPatch(allocators.getBufferByOverlay(key), key.getDrawMode(), key.getVertexFormat()));
     }
 
     protected void clearAll()
     {
         ArrayList<BufferBuilderPatch> buffers;
-        synchronized (blockBufferBuilders) {
+
+        synchronized (blockBufferBuilders)
+        {
             buffers = new ArrayList<>(blockBufferBuilders.values());
             blockBufferBuilders.clear();
         }
-        synchronized (overlayBufferBuilders) {
+        synchronized (overlayBufferBuilders)
+        {
             buffers.addAll(overlayBufferBuilders.values());
             overlayBufferBuilders.clear();
         }
-        for(BufferBuilderPatch buffer:buffers) {
-            try{
+        for (BufferBuilderPatch buffer:buffers)
+        {
+            try {
                 BuiltBuffer built = buffer.endNullable();
-                if(built!=null)
+                if (built != null)
                     built.close();
-            } catch (Exception ignored) {}
+            }
+            catch (Exception ignored) {}
         }
     }
 
diff --git a/src/main/java/fi/dy/masa/litematica/render/schematic/ChunkRendererSchematicVbo.java b/src/main/java/fi/dy/masa/litematica/render/schematic/ChunkRendererSchematicVbo.java
index 0408f31b26..e2ea1bd2a6 100644
--- a/src/main/java/fi/dy/masa/litematica/render/schematic/ChunkRendererSchematicVbo.java
+++ b/src/main/java/fi/dy/masa/litematica/render/schematic/ChunkRendererSchematicVbo.java
@@ -653,7 +653,19 @@ protected void renderOverlayReducedEdges(BlockPos pos, OverlayType[][][] adjType
                     if (posTmp.getX() == pos.getX() && posTmp.getY() == pos.getY() && posTmp.getZ() == pos.getZ())
                     {
                         //System.out.printf("plop 2 index: %d, ind: %d, pos: %s, off: %s\n", index, ind, pos, posTmp);
-                        RenderUtils.drawBlockBoxEdgeBatchedLines(this.getChunkRelativePosition(pos), axis, corner, this.overlayColor, bufferOverlayOutlines);
+                        try
+                        {
+                            RenderUtils.drawBlockBoxEdgeBatchedLines(this.getChunkRelativePosition(pos), axis, corner, this.overlayColor, bufferOverlayOutlines);
+                        }
+                        catch (IllegalStateException err)
+                        {
+                            // TODO: This is absolutely awful. Basically  some times the render buffer is closed
+                            //  while the this processing is happening but if this happens the work the thread was
+                            //  doing is going to be thrown away anyway so we just abort & no harm done. Really we
+                            //  should be using cancelable futures & coroutines to do this correctly but that is a
+                            //  task for not 1:30am when I have work tomorrow.
+                            return;
+                        }
                         lines++;
                     }
                 }