Directives from previous seasons may stay enabled on missions and cannot be disabled. This is in addition to the issue where missions remain at a previously selected difficulty setting, rather than resetting to Story difficulty after the mission is completed or the game is closed. In the video below, you can see that the Cool Skills and No Regen directives are always enabled, even though neither of them are selectable from the mission options. This is not restricted to Camp White Oak; I've also had this happen at Grand Washington Hotel, so I assume any mission can have this issue.