What do you mean "when a waypoint appears"?
What do you mean "a trigger will be activated"? Do you mean the trigger will fire, or do you mean that it will become active so that it might fire later?
If you are contemplating using a player waypoint to make something happen, forget it. Doesn't work at all in Veteran mode and very unreliable in Cadet mode. Don't play in C mode anyway. Vet is more fun and brings out the best in the game.