Apple Watch cycling through screens when charging
My Apple Watch 6 has developed an annoying habit of cycling through screens when it has charged to c100%. It shows the level of charge circle, the time and the watch face re-starting every 10-20 seconds. This behaviour happens whether or not the watch is in bedside (nightstand) mode, so is unrelated to that, and has continued through numerous software updates.
This is disturbing my sleep and - more importantly - that of my wife.
I have tried resetting the watch, unpairing and re-installing it, but nothing has made any difference.
Any suggestions that I haven't already tried would be very welcome indeed.
Apple Watch Series 5, watchOS 9