Ball hangs on rim

[OnePutt]

VB 3 whistle game after our GV game. Time permitting, I try to watch a quarter or two of the next game mainly to observe the crew. In the first qtr a layup is shot and hangs on the front of the rim as the defender smacks the crap out of the board while trying to block it. The ball rolls off the front of the rim. Official hits whistle and counts the bucket and the game moves on with no challenge.

I went in with the crew at halftime to see if this play came up. It did. The calling official explained that he believed the board slap affected the shot while on the rim. It sounded very nice, but I don't believe he had a rule backing him. Did he?