Yep, doubtful that shaft play is an issue. I also would suspect an issue with the finish on the shaft (either nicked or potentially even glazed) or some other seal head problem that could even be manufacturing related. Either the OEM or Racetech seals should be good (we don't use the other brand so cant comment). We do 100s of shocks every year and can't afford seal problems. Odd things can happen...
Cogent Dynamics Inc.