I can't tell on the film, but it I thought that #18 caught the pass on the try. If it was 78, obviously, it's illegal. And yes, the holder never lifted his knee, ball dead when he throws it, so it really doesn't matter WHO caught it.
But look at the TD play that came before that. Count the linemen. (Never mind, I couldn't see them until the slow mo. There are seven. There MIGHT have been a substitution issue before this, but we don't see when the sub came in).
Major screwups at the end of this game. Probably an issue of the crew getting caught up in the excitement of the moment as much as the players and the fans, and losing their concentration.