When I don’t have the tab with “Chat” in focus, it starts showing, in the tab name, “Chat(176)” IE there have been 176 new chat messages.
When I bring the Chat tab into focus it resets back to zero, because there are no chats in the channels that I am in.
This is, of course, very irritating - you basically have to learn to ignore the number in that tab, and regularly check to see if there are actually any chats in the channels you are in.
Odd… you are correct, I am a member of English and the counter seems quite accurate to new messages in there. I’m not sure where your phantom count is coming from!
I think it is coming from all channels, just as yours is. The difference is that you don’t notice the odd one or two discrepancy when someone actually says something in a different channel while you are not looking: it is swampped by the chat in English.