This should be fixed in the latest beta patch, where you now need to fulfill all the conditions as intended.
Also, the decision is available to you as a vassal, if you don't have the same religion/culture as your liege. Pretty sure that it's WAD, but I'll ask just to make sure.
Also, the decision is available to you as a vassal, if you don't have the same religion/culture as your liege. Pretty sure that it's WAD, but I'll ask just to make sure.