Since this snapshot, either on an existing (21w03a) or a new world, the game will go into a strange mode:

• Can't access chests / furnaces.
• Can't eat food (animation plays but food is not consumed)
• Blocks disappear when mined (wood or stone for instance)
• Placing a bed causes only half the bed to be placed

After this happens, attempting to save the game (via Save and Quit to Title) causes the game to hang indefinitely on the 'Saving world' screen with the earth texture background, the only way out is to end task in task manager. On reloading the game appears to roll back to the previous save state.

Leaving the game for a while while it is in this state, it will sometimes go back to normal. Very strange bug... Never experienced this in any other version including the previous 21w03a snapshot. It seems like some kind of lag issue but I am playing single player.