This seems related to the question: ArcRotateCamera's Radius affects the Rotation/Position of attachToBone Meshes - #3 by gbz
@Evgeni_Popov had solved this with skeleton.prepare()
. Maybe this could help resolve your issue
@equicolor, could you share which version of BabylonJS you’re using?
I also wonder if this question is related: Skeleton animations stalling / glitching