If Zombified Piglins (or a group of them) are angered, they will still target a player even after they switch to creative mode. If the player switches back to survival and then to creative again, they become passive.

This does not happen every time, in some cases they become passive and in others they become passive and then anger again after switching the game mode.

Edit: Zombified Piglins that are far from the player appear to stay hostile after changing the game mode, and the pack behavior is what causes the nearby ones which became passive to become hostile again.