Boss Drop Rate

Interesting. I didn't ever boss with a Xenon so I don't know if they are an exception or if it just works differently. Do you know if the Xenon skill triggers aggro? As I recall the Xenon Missile skills don't trigger aggro so that might explain why it doesn't consider those attacks worthy of making a player an active attacker, whereas I'm pretty sure both the I/L Chilling Step and Kanna's Ether Pulse trigger aggro. Familiars would also not cause a player to be considered an active attacker if this is the case because those don't cause aggro either, same with most final attack skills (but you'd need to attack at least once for the FA to trigger anyway at most bosses).

I don't think it has anything to do with aggro; I've been bringing a Kanna mule as a binder as long as I've been soloing. I've hit magnus with the teleport before, and the "aggro" notice on the boss notification bar routinely says my mule is "the most threatening enemy."
[MENTION=12966]Terebii[/MENTION]; has gotten quite a bit stronger recently, and I had him bind for my last two runs since Kanna's are so broken atm, and it didn't hurt my drop rate. He was making sure to use smite outside of the blue zone to reduce the damage dealt, however. Magnus considered both him and my Kanna mule as "the most threatening enemy" several times throughout the run as well.