Bump on this, still an issue.
The character still can target the floor, the caster runs there and is damaged as well. (It was a bit illogical for me to cast a meteor swarm to myself, that's why my first thought was to cast it on the ground. But I nearly died in the process :D )
Or if this cannot be fixed, please put a big OOC disclaimer in the spell description to cast this only on yourself otherwise you'll die :D