If the bars won't rotate in the stem clamp when you push on them with all your might, then it's probably okay. I'd be careful the first few rides when hitting big bumps. Those sometimes will have you putting more sudden force on the bars than you can do by muscling them.
It'd bother me though what is out of round or why this is happening. So I'd probably change out the stem, the bars or both. Though I wouldn't let that stop me from riding it until I can find what I want.
The pic is with the clamp tightened... isn't it?