Today I killed El Sueno the 3rd time.
My first kill was after i killed 2 or 3 underbosses that unlocked El Sueno.
The second kill was after completing the whole map with the same char.
For my third kill with my second char i destabilized the cartel completly but somehow in the wrong order. I played this char partly in coop partly solo with my ai squad.
In my coop missions i killed the underbosses before they were unlocked to me. I could accept these missions cause one of my team mates had already unlocked them.
It's not that annoying to me (i know both endings already), i was just wondering.
Same thing happened to me on the XBox, full completion & the wrong ending got triggered. The after action screen said something along the lines of 'You've only destabilized 100% of the cartel, replay when you've completed the game 100% for a different ending'.