/spawn from the nether sometimes results in falling form the world

CMDBOOK-2431 - Reported by Ardawen

So what happens, sometimes is that when people use the /spawn command form commandbook form the nether they get stuck somewhere and fall out of the world.

I do not get any error messages in console or anywhere, i tried to make it less bad by world guarding spawn from bedrock to sky and turn in invincibility and i raised the spawn point a few blocks up.

yet it keeps happening, sometimes, but only from the nether and not in an specific situation from what i can tell.

Any idea what it can be?