Why is ChatEnterCallback triggered when receiving group invites?

[kraxarn]

Decided to reopen this from the closed issue #391.

Why is SteamFriends.ChatEnterCallback triggered when getting invited to a group or accepting a group invite from Steam Community? Is there any way to check if the user is actually entering a chatroom or getting invited to a group?

The callback from receiving a group invite is the same from the last chat it entered.
I tried hooking NetHook2 into the Steam client and tried to first invite myself to a group and then join a chatroom. I'm not too familiar with NetHook2 and the Analyzer, but in the list I can see a message called ClientChatEnter, but only when joining the chat. When being invited to the group I only get a ClientClanState message.