It seems more likely something forcing it to play unless the game hasn’t registered they they’ve already played it (completed the achievement). It’s not like everyone is being bugged by this.
First test would be to exit the game, rename the TWW Interface folder and log in to see if it runs sans addons.
Once they know, they can delete the newly created Interface folder and rename the original back and work from there.
At a guess, SkipCutscenes would track the CINEMATIC_xxx events. Presumably the cutscene isn’t playing until after the initial PLAYER_ENTERING_WORLD which fires after PLAYER_LOGIN.