Since I dont see this listed in this forum:
Apparently a Wizard that has learned all spells in the game from scrolls already, or all but one spell in the game, cant level to 12, because you cannot skip picking two more spells and there are simply no more spells to choose from.
Reported in this thread:
https://forums.larian.com/ubbthreads.php?ubb=showflat&Number=911648#Post911648