Caster's with very large stats (intelligence and wisdom) can't lvl up. This is being caused by the current pre-requisite number of spells they must select when attempting to level. The problem is that their core stats are driving up the required number of spells to be selected to be greater than the number of available spells they have to chose from. The related problem is that as spell selection minimum is a current leveling pre-requisite, and as there are not enough spells to chose from to meet the requirements of high Int or Wis casters, this pre-requisite leveling bug/blocker is therefore disabling these high-stat casters from leveling up (causing game progress stasis).
I have screenshots if need be.