I have been experiencing this issue, for months, where my body glitches. It either happens with my legs or my shoulder and nothing I do has fixed it. To be clear, this issue can only been seen on my end and only in the Firestorm viewer. I have tried using older and new versions of Firestorm but they don't make a difference. Neither does using different bit OS types. I have taken everything off and reset my avatar but still nothing is fixing it. I'm seriously desperate at this point. It is distracting and makes me not want to play.