Soppon
I was having a similar problem on my rogue... So I'd stealth, ambush/cheep shot something and my action bar would lock up. I later determined that it was blind flash count screwing up my action bar. It may be some other mod that's interfering with Bartender.
I was alos having a TONNE of problems with CT bar mod. So I've switched to bongos and everything has been good. Yeah I just noticed that it tends to happen when I go from stealthing in cat form to normal.
I also learned that if I pop into bear or cat and then back out I can reset the bar with out logging out. Still annoying. I'll check my timer mods and I think I may use the CT bar mod so I'll switch it as well.
Thanks for the advise.