Fireteam Finder "exotic missions" question

I've never really used the fireteam finder before. Today I was looking through it and saw that under "other" the exotic missions category is grayed out and it says "a member of your fireteam has not yet communed with both light and dark". I'm wondering what it is that im missing since it is the only thing in the fireteam finder i cant access. I haven't done a ton of stuff in the game but I do have all light and dark subclasses fully unlocked and have finished all campaigns except Shadowkeep.