I'm not sure if this has been covered or not, but my TV has just begun doing this a few weeks ago immediately after a software update.
It's an element model e4aa58r that is now running software version 10.5.0 build 4210-ay. It began doing this the same day it updated on 1-9-21.
Is there any way to try a forced version downgrade? I tried talking to element support and they basically just said to contact a repairman, but I really want to try ruling out a software issue first.