I also saw this in the rulebook which makes me think your OP was even more correct than I originally thought -

VIII. Safety B33 intercepts a pass at the B-10 and returns for a touchdown. As he is coming down the sideline covering the play the line judge drops his flag after he runs into the Team B head coach who is just on the field of play near the B-40. RULING: Although this is a foul that takes place while the ball is alive, it is treated as a dead-ball foul against the team because it is committed by a non-player. The touchdown counts and the 15-yard penalty is enforced on the try, the succeeding kickoff, or from the succeeding spot in extra periods.


(It was like 6 pages from the end of the rule book)


So, yeah, unless Harlan interferes with a player on the field, that is definitely ruled a Touchdown still.

I jumped to conclusions too quickly.