Any tumbled die like this (identifiable by the polished surfaces and the smooth edges) gets deformed in the tumbling process. The solution is one of three things:
Accept this as your lot in life
Look for precision dice
Buy enough tumbled dice that you’re grabbing a random die that is deformed differently from all the other deformed dice every time from a pool at the center of the table
Any tumbled die like this (identifiable by the polished surfaces and the smooth edges) gets deformed in the tumbling process. The solution is one of three things: