No, this happens to me too. On my first play through it started happening in Solitude: if I exited a building, a dragon would collapse onto the ground ragdoll style and writhe/twitch around a bit before going still. You could completely walk through it, just like a dragon skeleton, and the game would still show its name and let you search its body although it'd be empty. In my second play through, I had a dragon randomly fall to the ground behind me, it died and gave me its soul/body loot and so I thought it just maybe, I dunno, crashed. Anyway, since then I've had an identical dragon pop up in certain places twitching and jittering around just like in Solitude - as TME said, they're sometimes stuck between walls too.
Never happened to me. Must be a glitch in newer patches?
