Just wanted to clarify this so everyone is up to speed.
To get the Cor cutscene, you need to finish the 3 base missions with him.
If you don’t, Ignis will say that he’s busy with other stuff during the Cerberus battle and he won’t turn up.
After the Cerberus battle, then Luna pops up.
The flashback with Cor does make sense, but only if you complete the Cor related quests before.
It does suck that the cutscene is triggered by doing some minor stuff before though.
I’d also like to mention that when fighting the Kings of Yore, try finishing the battle with different party members.
Every member has a different finishing scene
P.S. Star of the Rogue is kinda sexy...