As I mentioned previously, my ranger, samurai, and ninja were having problems learning 7th level spells in their native schools. All of them are beyond level 7, and all have at least level 7 in their native schools. I have also not spent any points on sorcery for them, until recently.
I spent one point on the samurai, raising her sorcery to around 1-3/4. She can now learn level 7 sun spells.
I have not spent any points on the ninja, who just reached level 12. Her sorcery is less than 1-1/2 (growing naturally). She still cannot learn any level 7 spells.
It appears there's a trigger in the sorcery skill to allow you to learn level 7 spells. I'm not sure if it's a minimum skill level or merely the application of a skill point, but I will keep the ninja going until her sorcery naturally reaches level 2, at which point I should be able to determine what the difference is.
Just thought I'd post this update, and relate my late great marine battle. Swimming in the waters of the enchanted sea, we were accosted by six sharks, a trio of dartha eels, and a pair of lagoon piranha. Everyone has levelled up except the warlock...
More later... like Saturday, probably. Got to go to Virginia tomorrow.