Vassal's obligations have already been changed

[Saul Goodman Is In Your Walls]

I'm currently playing as the petty king of Munster, and I'm trying to run the Norwegians and Nords out of Ireland starting with the earl Olafr of Ormond, and I'm trying to take away his titles with limited crown authority on but I am left absolutely stumped on this. His contract randomly changed without me knowing anything about it. Now when I try to give him a fair offer of no title revocation protection with low feudal levies, and I can't. I have gone through two whole characters and it still says "Earl Olafr's vassal contract has already been changed". Is it time to make him go to the forests and get killed by a hunting "accident"?

[armyissue69]

1st off...never allow anyone to have "no title revocation". 2nd Title contracts change, usually, when they had a liege previously and they maneuvered in such a way (war, hooks, etc) as to modify their contract...once this is done, you gotta wait till they die. 3rd I generally keep taxes at normal and levies one step down (if they rebel I'm close to my levy level anyways so I have a good gauge).

Once a contract has been changed...you have to wait for them to die, their title destroyed, changed hands, revoked, etc. It certainly is odd that you can't make changes like in real life you could approach a vassal and be like, hey you been good, I want to reward you with a better contract (Fief obligations)...this should be allowed.

[PostalGibbon]

Feudal contract alteration was "adjusted" some time ago in one of the patches.
Before change you as a liege you could just revert back any alterations your vassal blackmailed to the contract instantly after the change. You suffered tyranny penalty and that's it.

Now there is "cooldown"( one change per lifetime of ruler or vassal) either your vassal needs to die or your current ruler needs to die before you can change feudal contract again.

Feudal contract changes usually happen when vassal blackmails liege and gets a hook and then uses that hook to alter their feudal contract.
Then there is some events example like when vassal is broke he/she comes to you begging for gold one of the option if you give him/her a tax relief you have now altered feudal contract and cannot do it again unless reaper visits.