Thanks guys! I don't have locking tuners on this one because they were purchased for me as a gift and the person who bought them didn't want to spend $65 to get locking ones. I have been thinking about upgrading for a while though. They're Gotohs though, so they aren't total PsOS, and I don't have the problem with any of my other strings on that guitar.
Next time I change my strings I'll go through the list of things that could be causing the problem and address anything I find, and if I still have the problem, I'll grab some locking tuners. Maybe that's what my husband can get me for our anniversary.