Finally get rid of the very annoying double beep issue on my car. Have inspected just about all microswitches on the doors and arm rest lid - opened up the lock mechanisms on both doors and trying to sort the issue also on mechanical wear items there... no lock in over a month.
Issue was a bad connection on the rigth side door wiring harness to door lock mechanism. Cleaned it well with electric cleaner and lightly sanded the contact points. Problem solved
I also ordered a new wire harness connector to be installed there probably during next winter.