[Don't think this has been brought up. Did a search; if I missed it, sorry!]
"Incomplete illegal forward pass" is one of the things that can trigger a 10 second runoff. My guess is that they wanted to make the runoff to apply when a QB (behind the line) simply dumps the ball into no-man's land
to conserve time.But as 3-4-4 is written, it doesn't differentiate between dumping the ball to stop the clock and (accidentally) being beyond the NZ making an earnest attempt.
55 seconds left in game. Team A trails by 4. No timeouts. 1/10 at midfield. Under pressure A12 rolls out of pocket. He gets to the B-49 and heaves a deep pass to wide open A88 in the endzone.
Whether or not we have a runoff depends on whether or not A88 makes the catch?

This is not a foul that causes the clock to stop. Moreover, it's not even a foul committed to conserve time. (Granted, most false starts at the end of the game probably aren't committed to stop the clock either. but at least with those, you can correctly say that Team A might benefit from the blow and throw.)
I can't imagine a play like the one above, where a receiver drops the ball, is one that they intended to hit with a runoff.
Could this be fixed by adding "to stop the clock" or "to conserve time" to the end of 3-4-4-a-3?