Selection Tool > Move Error > Layer Change
This is an issue I encountered. When you use the selection tool and select an area of pixels and then begin to move them, the box then changes to the solid box which allow you to move your selection around. If you click on another layer while the selection is still in "move selection" (with the solid square around it) then it will automatically be moved to that new layer. This is very frustrating when switching between layers quickly since if you move something and then forget to double click to remove the move selection and return to the normal selection it will suddenly be on the wrong layer. This happens every time you do this so it's easy to recreate. If this is intended then I would recommend changing it, if not then please fix it. One of the most painful bugs I have to deal with every day.