Actually, it gets wierder than that. I just tried to get back after my previous post, and the 1st one that responded  showed me this thread with an empty space in place of my post . All it had was "Reply"  and a blank post (NOT a reply box, an actual post, as if I'd been thrown into a temporary, server-only  version of the thread).

When I slowly backed out of that,  the next that became available was this forum. Except that the top few threads were missing (including this one). Actually, it might have been there but not marked as "new". I didn't check that. I sort by "latest reply".

Oh, and I'd cleared my browser cache when I 1st noticed the problem (left 'rosity, closed Mozilla, restarted Mozilla, cleared cache, re-entered 'rosity.

The problem seem to be unique within threads....

Cheers,
Diolma