I actually asked this, and got a response that they are looking into a good way to word it, but I think what they were saying is that in that case, the Roc is NOT supported, and would take damage (IE, that it really only is supported if it can end in the space adjacent to the friendly unit). The previous ruling's wording didn't account for that aspect.
I'll let you know if I get a follow-up, though.
It's a little weird, in that your own unit is the reason you're taking damage from a retreat, though, since without the Rock Golem the Roc Warrior would be fine. I assume that is the ruling as well, but it'll be nice to have it clarified.
Well, consider it like you try to run away because you are shot in the back, but you have your dumb friend standing in your way.