Southwest MB

I have attached a video for your opinion on. I’ve always worked on this car as needed. It really is a babied 22k mile CLK350 cabrio. Came back from a 500 mile trip with it on Sunday and went to check the oil as I just changed it before I left. Saw a slight oil leak near the cap so I ran the engine with my head under the hood and noticed the belt tensioner was oscillating and thought I saw a slight lateral wobble on the vibration dampener causing the tensioner to vibrate as it is. I’ll admit I’m more family with BMW inline 6 and there V8’s of 20+ years ago. Does this M272 tensioner and dampener seem ok to you? Thanks