Easy way to test:
Place respawn anchor in spawn
Charge with glowstone
Deop or join with second account subject to spawn protection
Click respawn anchor
It explodes client side, but not server side due to spawn protection
You are on fire, blocks are destroyed, and you start glitching as you try to fall client side but not server side
Beds in the nether do not have a similar issue due to client side check on the explosion code
Possibly related to MC-175169 but unclear if same cause (could be due to client/server using different randomness).