Camera Error turn the power off and on again" fix?

[Jack Sparrow]

A7m2, Japanese body. I got this error frequently about a year ago, and then it magically and thankfully went away for a year. Now it's back. On startup the camera says "camera error turn the power off and on again" after a few seconds. With the right timing, quickly turning the camera on-off-on can sidestep the issue sometimes.

Appears to be an issue with IBIS initializing when the camera boots up; the trick to avoid the error works but it looks like the sensor is not in quite the right place so I assume IBIS isn't running at all.

Anyone else have this error and fix it? Google suggests some temporary fixes (like whacking the camera) and replacing the whole sensor/shutter mount assembly (which sometimes fails again later).