Game crashes when entering a bed with a repeating command block setting a player's spawnpoint

Summary:
When a command block sets a player's spawnpoint and the player is in a bed at the same time the game crashes. This bug doesn't work when friends are on your world. On realms it will crash the server for around 45 minutes and will rollback.

Steps to Reproduce:

1. Get a repeating always active command block and put in it "spawnpoint @a".
2. Set time to night.
3. Try to enter a bed.

Result: Game crash