This is an issue I've just recently had with my X-T4. When I turn it on there's is a very loud vibration. If it's on my coffee table, it reverberates through the table. When I look at the sensor it looks like it's slightly moving. It will stop when I review images, and starts back. After a few moments I get a message saying to turn of the camera and turn it back on again. I have no idea what the problem is other than maybe something is wrong with the IBIS and sensor motors or something. Has anyone else experienced this? It almost sounds like I may need to get this thing repaired.