I don’t know if this has already been discovered and posted elsewhere yet or not, but I accidentally found something about the new mayhem 2.0 tonight.
Apparently a lot of rare spawns will respawn after changing your mayhem and reloading the area. And without the ads. All you have to do is either reroll the modifiers, or change the mayhem level and then apply.
Makes farming some of these guys way more bearable on console with the load times.
Only tested with a handful of enemies but it works with El Dragon Jr, Boreman Nates, Indotyrant, and The Unstoppable.
Did not work with Demoskagins, Captain Traunt, Gigamind, or Hekle/Hyde.
Again forgive me if this has already been discovered. Happy farming!