I’m playing through Warlords of Draenor content on my new Mag’har Orc. Four of the 11 followers I have so far were upgraded to epic when I got them. Three of those 4 have two of the same ability. Ka’la has two Evasion, Tormmok has two Taunt, and Blook has two Recklessness (Mulverick has Kick and Disengage).
I have had hundreds of followers across a dozen characters. This has never happened to be once before. Something must be going wrong when they’re upgrading.