Flagsticks are missing on mobile games anyway. It’s happening on approach shots on tourneys and head 2 head games. Reported by several in our club and is not Course specific. Been going on for a day now.
The work around is to exit out of game, close the app, reopen and the pins come back for at least one hole. If you do that twice in H2H though you will be disqualified.
I posted this in the bug log forum too as this makes the game unplayable.