Can't Clear Chat History

Hello

We had a resource mailbox for booking our Boardroom. I converted to a full user with a standard license.

It seems to be working fine except when I first sign into Teams on a machine with that account it shows a chat history from a meeting back in June. The meeting doesn't show up in the list on the left for me to leave/delete it. I can't find anywhere to hide this chat history at all.

I've logged into this account on multiple machines and on the web for teams so Windows 11, 10 and Chrome. This is MS Teams for work. I do have admin access to our Office setup if needed.