I've started with Image retention from the clock on Always On Display. AOD still moves around the screen like it should do, but as soon as I unlock the phone, I can see the outline of the AOD click for roughly 10-20 seconds.
Nothing else gives images retention, just AOD. Tried websites and leaving them open for a while, but no, doesn't do it.
It's bizarre?
I've disabled AOD for now and reported it via the members app.