This event randomly popped up while I was playing. My character is the Sunni Caliph. I have a custom faith with the Pacifism tenet; I thought I needed Struggle and Submission to initiate Great Holy Wars at all. Also, why would I need to "retake" the core regions when my faith already controls all five holy sites? And why didn't I have any decision or input if my own character is the one declaring an era of renewed Jihad?
This is bizarre.
Seems like one of the many things that Paradox frankly didn't prepare for. I'm fairly certain that when this event fires, by default it chooses the Sunni Caliph as the leader calling for the renewed Jihad, regardless of the tenets present in the Caliph's preferred flavor of Sunnism. The Jihad-renewal event seems to have been cobbled together back on release when the game was about as fleshed out as freshly flayed skeleton, and Paradox never really got around to expanding or just modifying it to account for, say, the Sunni Caliph just really not believing in religiously-justified warfare. I would hope they would get around to reworking the systems at play here, but I also wouldn't wager so much as a half-eaten bag of corn chips on it.