Anyone else have an issue/bug where a certain faction won't break alliance with another even if accepting a trade to do so?

I am trying to break a target off an alliance. I offered random towns or money to their allies to break the defensive or military alliance with them. But one (Etaine) won't break it. They accept the deal, take my town, take my money, and keep their agreements without breaking them.

Potentially the worst trade deal in the history of trade deals.

Immortal empires playing as Belegar trying to get everyone to break up with Orion, Tyrion loves him too much apparently.