In my current game, the AI sovereigns seem to be buying an inordinate number of leather greaves. Twice now I have demanded and received their surrender, and the more recent victim, Ceresa, had 66 sets of leather greaves in her inventory when I gained control of her.
She also has two horses, but that at least could be from trading with a hero that got wargs instead, or something better. I can't figure out why one hero would need 66 sets of leather pants though. A much earlier defeat of Magnar had a similarly large supply of greaves, though I chalked it up to a fluke at that point and don't have a supporting screenshot.
The game was started in 1.5 beta, and has since updated to 1.5 release, though obviously not all of the updates would apply to the save game. Having not seen any other similar reports, I thought it might have made it through the beta, hence the bug report on the older version. I'll update this thread if I see the same thing happen in my next game.