While I don't remove the sideplate any more, my latest J-frame purchases are very dry, with little lubrication. On the firing line, the triggers stick in the rear position after about 50-60 rounds, and must be pushed forward. After cleaning, I put 2-3 tiny drops of oil on the trigger. Just a smidge. This has cleared up the problem as it seeps into the action. Guns work fine on additional range sessions. I also vote for the rough rebound slide as a contributing factor.

Kaaskop49
Shield #5103