Ok ok ok it's probably been said before.
BUT my theory is about when Cassian and NESTA finally get together and all that stuff- cus we know they will.
Remember how Cassian tried to get Rhys to calm down after the mating bond thing by flirting with Feyre and baiting Rhys into a fight.
I bet you this time it's going to be Mor flirting with Cassian to bait NESTA because we all know she is the the jealous one in that relationship π