At our wit's end here. We are both veterans in SL (arounds 10 years) and have gone through multiple possible solutions here... My friend's avatar will randomly stop posing in whatever pose/animation she is in, all the time. Even just standing with a static pose it will break at random times. If we are sitting somewhere, after a while she will just stop animating entirely and stand as if having no animations loaded at all but still be on the poseball. She is the only person Ive known in SL with this issue..