Report for remember stuff.
When you create a clan chat on an iron man account you aren't able to permanently leave the chat. Only way I've found that allows you to leave the chat is to go to battle royal and join a squad and leave, this allows you to join another clan chat in the meantime but if you don't and relog you are back in the old chat. Also if you join a new chat and use battle royal to kick you from it and relog, you are back in that chat again.
Tested this on multiple accounts, problem seems to be 100% related to iron men as I had no problems on both older normal accounts and new normal accounts, whereas I had the problem on all iron man accounts I tested.