Two days ago tried to play the Tanks,Tanks, Tanks crossover playlist and the third mission: The Ark would not load. Once the third update downloaded I tried again. This time it loaded but started me on the final rally point.
Now I just tried playing the Epic Battles playlist. The third mission: The Covenant won’t load for me.
I don’t know if its coincidence that they are both Halo 3 levels. I tried them individually on campaign mode and they work fine