Quoted from Eskaybee:Here’s another thought, simple check which may lure in other technical a-holes, but Screw it - at least I’ll offer ideas and help. But, check the gap of your flipper(s) and Make sure they’re not dragging or getting caught on the playfield. I know some people have had that issue on newer sterns. I believe the simple check is being able to place a credit card smoothly through the gap.
Most of the parts stores sell a flipper gap tool with their rebuild kits which is 1/32" thick. A credit card does essentially the same thing. For whatever reason, it sounds like your mechanism does not have enough space and should be an easy fix with an allen wrench. I've attached the Service Bulletin #108 that discusses this topic for the SEGA-style flipper mechanisms and all mechanisms have similiar gap requirements in this respect. Look at the middle of the second page and they specific under the note that "1/32" UP and Down movement"