Fugg it.. It may be more trouble that it's worth to track down for now. It'll go away as threads fall to the wayside. For our longer running threads " Wife's Tata and Morning Geezer" I can migrate them and see if that helps if this is indeed the case.
I think what you need to fix is using Firefox! I have been using Chrome for 3 years now and love it. Someone opened IE on my computer the other day and I thought it was going to blow up. I have Safari but don't use it much.