It was Firefox and IE 6.
Interesting because I can't duplicate it in either. I don't even get the Fetching preview notice - the preview just comes up. :- But I'm not going to worry about it unless/until it keeps happening.
what it is showing is spoiler with the colon, but it is not hiding it.
How very odd! It was working perfectly fine for me before I set the regular members permission to allow members to see/use spoilers, but now it's not working at all for new spoilers beyond the word spoiler showing up. BUT odder still, spoilers posted before I set the permissions ARE working!
We've joked before that the forum is haunted.
But in instances like this I really do wonder if it isn't actually true!
But seriously, I'll do some experimenting to try to get to the bottom of this latest bizarre development. Something very wrong is apparently happening now with the way the system is processing the spoiler tags before posts are being written to the database. I've gone into the database and manually fixed your post, but until I do get to the bottom of it, people probably shouldn't put any spoilers in their posts, so I've disabled the permissions again...