As usual with WoW patches, patch 2.4.2 includes a couple of wild bugs. My personal favorites(and by favorites I mean I absolutely hate them) are the bugs(changes?) to the Archimonde encounter.
Now, this may just be "Onyxia Deep Breaths moar" syndrome, but the official Dungeons and Raids forum has some pretty substantial(mostly anecdotal) evidence to the contrary. What are these bugs? Well, it seems Archimonde's Doom Fires are spawning on top of the melee and immediately chasing them, rather than travelling out towards the ranged first. Seeing as this fight is generally carried entirely by the melee DPS, that changes the fight quite a bit. The second change/bug is that... your main tank can now be Air Bursted! Hooray! That isn't annoying at all! Sarcasm is sweet!
Archimonde certainly isn't the most difficult encounter in WoW and it is still able to be beaten even now, but I personally hated this encounter with all of my heart and soul to begin with. This doesn't help much. Admittedly, I haven't seen these bugs/changes in action personally yet, but I do not ever want to see them, either. Have I mentioned I hate Archimonde?