Scripts for beginners.

Since the primary objective is the only one, it’s possible that if it’s the only objective, the victory is automatically awarded upon completion. Usually, for this purpose, a main objective is created that remains active from the beginning to the end of the game (for example, not losing the main hero).
You can also experiment with the Ignore flag:

Ignore – when set to “true,” it is not taken into account when checking for victory or defeat.