Or returning air pressure tries to escape through the bearing edge/head connection.Keep a camera on the thing.
I just can’t imagine how this could happen, there should be enough friction to prevent movement. Or there’s some kind of hardware issue that is reducing tension on a strike, and the head creeps slightly with each it. Or the head is defective and not responding as excepted.
Or you have a haunted bass drum, IDK.
Is the reso ported? If not, try taking it off for a while and see if the problem persists.