I guess you could try placing a straight edge across pulley faces from the hub pulley and see if they all align. Inspect all of the pulley bolts and any protruding center hub for evenness, possibly a pulley mounted with a tilt. Next would be to check the pulleys themselves with a straight edge to make sure they are true.

Last thing that comes to mind is replace that serp belt, its got a lot of cracking, and if worn in by your bad tensioner before, it is likely skewed now on a good set up and not traveling true under load.

Good luck

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)