During the beta 1.17.0.52 in multiplayer, books can turn into random blocks when touched.

Me and my friend have tried to play minecraft 1.17 beta together however, when we join eachother's World, the host can play normally but the player who has joined have blocks turn into random blocks, but it only effects their side of the game. The host, or any other players, cannot see that the block has changed except for the player it happened to.