How Give up claims peace term works ?

Hello, I'm facing a problem here. Playing as France, i want burgondy royal mariage but they rivaled me. I declare a war on them to stop the rivalry and force them to give up with the claims they have on me.

But here is the problem, before the peace, they want several provinces for me, up to -95 opinion :

Burgundy opinion on France before the treaty

Sum up of the peace deal (for non french users : Burgundy and dependencies give up on cores in Bourbonnais, France and Orléans, Burgundy is forced to unrival France)

Peace deal

And after the treaty (I waited for mensual tick and even annual tick), almost the same :

Burgundy opinion on France after the treaty

Is this a bug or anything ?

How do I completely force them to give up on claims ?

Thanks ! 😄