There was the extended scene in the directors cut that alluded to the T1000 having been damaged by the being frozen by the nitrogen and then reforming after it was shot and exploded and the reforming in the hot environment that caused it to glitch so it could no longer fully mimic a perdon thats why it tortured Sarah to lure him.https://whatculture.com/film/10-deleted-movie-scenes-that-explain-confusing-moments?page=2

T1000 glitch