There are dragons who will not attack unless provoked. Maybe they were attacking nearby monsters? Only had one occasion where a "neutral" dragon flew by me. He didn't like it when I stuck an arrow in his foot. 
Bear in mind, I wasn't patched when I saw this.
The scenario was, I'd gone to talk to a guy on a mountain. I came out the door from inside the mountain, Patrolling random dragon shows up. I would hit him with an arrow or two, he would land and breathe on me a couple times, it was on. Then he'd do one of two things. He'd either go find some other monsters to fight and basically work his way away from me, which I've seen before and think it's working as intended. The other thing he'd do is he would spiral climb over the mountain I was on until he was wee tiny, then eventually he would either vanish going up or come straight down and seemingly vanish behind the mountain. He didn't appear to be landing, just vanishing once he was out of sight, and the combat music would stop.
I probably reloaded from the door 20 times, just trying to figure out what was going on with it.
Not a big deal, just struck me as odd. I love how they fight with everything they can see.
The one thing that really strikes me as awesome with this game is the fact that if you shoot an arrow straight up, it will come back down and land, sticking in the ground. It will also hit stuff on its way down, not just up. That's the kind of projectile modeling that I find lacking in many, many games.
Wiley.
