Is it redundant to use “Trigger once” in addition to “At the beginning of the scene”?
No it’s not redundant!
The condition “At the beginning of the scene” is relative to the game, more precisely the all start of the current scene. All events of this part are exclusively executed once at the start of the scene of the game.
As “Trigger once” is relative to the current condition, not to the current scene.
At the beginning of the scene will always trigger only once when switching to that scene no need for a trigger once in an event using the at beginning of the scene condition