Qara Qoyunlu has 6 vassals in my game...
I would expect it's not done on purpose. Vassal create claims, so overlord probably give claimed provinces to vassal when they want nothing else. They also happen to press vassal claims. It's still acting a bit weird though. I had an AI press its vassal claim, offer to give the province to vassal in peace deal and the AI refusing because it wasn't interested in the province...
No, Ryazan didn't have a single claim on these lands.
is it posible Ryazan did that before vassalization?