I believe the events about dragons descending on the battlefield are bugged right now. I started my playthrough as Dorne. Reloaded two-three times, as Westerosi used dragons more effectively than they ever could in Dorne. Nonetheless:
I keep getting messages of people descending on the dragons, even when those people doesn't own dragons. Already gathered 1,5k prestige killing non-existent dragon. Only 'true' dragon-rider I faced so far was Aegon... and after the Dragon-Slayer event popped, I was informed:
(note, this isn't event after Aegon's, only Orys - as above)
but, moreover, Aegon's beast didn't die. Instead, game informed me that
my (sic) dragon was killed by myself. I suppose I should be...
Happy?
BTW: is there any possibility to make something akin to defensive pagan homeground bonus, only on cultural ground? Would make very good for modelling defensive focus of Dorne, as Targaeryens in earlier start date seem very fond of invading it.