Hi again
Yes, I did manually turn "disclose when I'm online" off, as I did what devices I am using (which the Moderator had noticed). I have just turned both back on and logged out and in and refreshed a couple of times and the forum is now working properly.
I would rather not disclose that information to all users but until the extension bug is fixed, can survive!
I will let the Moderator and other user know of the issue and the solution.
Thank you so much for your help with this. I'm not a programmer, so would never have found this. Much appreciated (and I am sure too, by the other user experiencing this).