Look, it was something I didn't know to be honest and I did some searching on the internet and it seems that this "regulation" is valid. But now if someone has video of a match where the ball hit the woodwork without hitting a player then that is surely a bug and should be reported.
It is also good to mention that if a shot hits another player and then the woodwork it should be recorded as a "shot blocked". If it’s not please report it inside Bug Tracker!