I’ll ask some folks who played more of the original game how Item Lore is supposed to work. It seems possible to me that there is a bug here. I also have a wild guess that it might be more to do with your highest Item Lore score than your combined score. But I’ll look into it! Thanks for pointing this out.
The answer I found for you is that (in the original game) it IS based on the party total for the stat, but it does nothing for items that are pre-placed in a town or dungeon. It only works on items that drop.
I think OpenBoE is doing it the same as the original, but could double-check. This would explain why it’s not affecting the Fort Talrus supplies.
