I’ve upgraded from Studio to Animate and the pivot points in animate are driving me nuts (Though I had difficulty with them in Studio too). I’ve got my object (a leg) and I drag the pivot point to the top of it. Then the leg reappears somewhere else. What’s that about?
You should post in the Animate forums in the future for Animate questions - this is the Pencil Check Pro forum.
However I’ll answer your question anyway. If you have already put animation on your drawing layer with the transform tool, and then you move the pivot, then the transformation is going to update so that it now uses the new pivot to do its transformations. All transformations (rotations etc) are done in relation to the pivot point.
You should clear all keyframes and reset all animation before setting up your pivot points.