Q did it.

What about the shot that made it into the final cut where Worf and someone are fighting and he knocks a hole in the set and it’s just wood?

It was obviously a temporal anomaly.

Or each grain of rice is a Q, just paying a visit. An ensign tried to vacuum up the rice before the ceremony and was turned into a bowl of petunias, so Janeway took the hint and left the rice alone.