It is my board and I am the administrator, this is happening on all the cards in my board. I have cleared all browsing history and restarted my machine. The "comments and activities" box is showing but as soon as I click in it to write a comment the box disappears and is replaced by a greyed out save button.
Everything was working fine prior to the Christmas break but I came back to work on Monday when I first noticed this issue and have had it ever since.
I am using Edge (can't use any other browser as laptop belongs to my employer and is locked down/restricted).
Has anyone else encountered this issue?