I and others have noticed a new problem with newly-uploaded animations: sometimes the hips/legs/feet shift unaccountably, as was the case back in December for a while. E.g., I made a "stand" for an AO, and I did not change the hips or legs at all; and yet when it's uploaded and plays, my hips, legs, feet all abruptly shift about half a meter every so often. What's odd is that the problem doesn't necessarily recur regularly; sometimes it happens every loop, sometimes not. It may be somewhat linked to whether I move the mouse or type something, but I'm not sure.
Luth Brodie showed me a similar problem: she animated a figure with both legs/feet still, but her left leg wandered out about six inches and wandered back in.
Have you Lindens noticed this? If not, could you try uploading a simple stationary stand and see if it's really stationary? If you see the same problem we do, any timetable for a fix?