2.4.4 FUYZ Banishment bug

[Riekopo]

I've got this Duke imprisoned because he was part of a lower crown authority revolt against me. When I looked at the banish option it said I would be banishing him for no valid reason which doesn't make sense to me. He was part of a revolt. How isn't that a valid reason? One thing I noticed also is that banishment affects vassal opinion more negatively than execution does which doesn't make sense to me either.

http://i.imgur.com/5EvYRps.jpg

http://i.imgur.com/67ckFIb.jpg

 

[Maeldun]

Did the duke in question hold his current titles when the revolt started, or did he inherit the title after war was declared?

Can you revoke his title without incurring tyranny? If not, then he is not flagged as a traitor. If you can revoke but can not banish, then it is likely due to the many changes that have been made to banishment. Its purpose is unclear as currently implemented and seems to make sense only with unlanded characters.