The title sounds a bit dramatic, but that's exactly what's happening with my new (5 weeks old) a7r4. It probably did the same straight out of the box, and I've only just noticed it. It might be normal, but it certainly sounds disconcerting. Symptoms are: If the camera is tipped or gently shaken when powered off, a definite rattle can be heard. With the lens removed, this can clearly be seen to be caused by the sensor shifting up and down or side to side. As soon as the camera is turned on, the sensor jumps to a 'locked' position. I'm guessing that this behaviour is caused by the IBIS servos, that simply let the sensor flop about when not powered. However the amount of movement, and audible knocking noise from the sensor when the camera is gently jolted, doesn't look or sound like it was designed to do that. Anyone else have an a7riv that 'rattles'? Oh, I've also noticed that occasionally the focus will jump as the shutter is pressed when steadyshot is engaged. Presumably under command from the Z-axis servo. However, instead of keeping the same focus, it shifts the focus from where it was manually placed.