This happens when you have the auto tune option set (settings , broadcast, autotune). TV will retune itself, usually in the middle of the night, and then requires confirmation of which region you are in when you turn it on the next day. If you disable the auto tune the problem will go away, but then of course you dont have the benefit of automatically finding any new chanels which may get added in the future.
To be honest, in the end, I did nothing and one day it stopped asking for the region. I assumed that the firmware must have been updated as I didn’t make any changes.
Sorry I can’t be more helpful.