FB group messenger chat bugs

[Excalibur]

Bugs:
The chat keeps disappearing from chat list. The workaround has been to save chat as a favourite in Chrome. A friend has the same issue with this chat and he's using Apple-mac.

In the same Chat, when I click a pic to blow it up, it goes to blank page. Apple mac friend has exactly same issue.

W10, up to date except for (KB5030300)
Chrome, as I write I see it has an update so about to install it.

Thanks.

[Excalibur]

Discovered a partial workaround for pics not blowing up. Select "Open image in new tab". This enlarges image a bit, but not really enough.
My regular chats are working perfectly btw.