I fired this bot up after an extremely long hiatus.  Decided to test it out while farming old Cata instances.  I managed to get through the entirety of Blackwing Decent, but once I got to the final fight with Onyxia and Nefarion, the rotation stopped doing anything.  It didn't matter if I was targeting Ony, Nef, or one of the adds, the rotation flat out wouldn't do anything.  Just stood there.  This was on a frost mage at first.  I tried three different class profiles, nothing worked.  I switched to arcane, same thing.  Just won't work.

It's ONLY this fight (so far) that is doing this.  It worked just fine for the rest of the instance.  I haven't tested other instances or other classes yet.

Hello, can you share your log file (after get this problem). Do you have activate option "start fighting with elite" and increment "max unit near" (in advanced general settings)?