Sorry for the hiatus. My brother ended up deleting that original after we got frustrated with it, but we are in luck! My newest save has a repeat of the bug (tested it and it seems to be the same and this time I think he might have been shopping at the same time I was).
Bartering does indeed seem to fix it... though if you offer the normal price they won't accept and you have to offer more for it to amount to anything. After buying one through it though I can buy them like normal for some reason. My brother also got me to try bartering a cheaper item first before buying the skill book and that seems to work as well.
Doing party management seems to have no affect and I do have an earlier save that I can buy them from. Since it seems to be save dependent, I don't think its related to the cache.
I will be sending the earliest before, the affected save, and the save after the "fix" so there can be a timeline for it. Maybe they'll figure it out and make sure the bug doesn't pop up again.
Thank you for helping me with my issue. I do appreciate it.
