Another from Discord user bug report.
When leveling a spontaneous caster from an out level to an even level, it gives the spell caster an extra spell learned (Sorc gets 1 2nd level spell at level 4, but in game with Spellbook Merge gets 2). Replicated just the Sorcerer 3->4 aspect, but user Loub#0125 states it happens with all spontaneous casters.
I realize you are mostly away from Wrath's modding scene, but submitting the issue in the case that someone submits PRs.