Failure to eject. - Sylvan Arms AR-15 f/9mm Glock Conversion Block

I own 3 AR 9 pistols, 2 with dedicated lowers (Aero, Joe Bob)& one with an AR15 lower with a Stern Defense 9mm mag well adaptor. I recently bought this Sylvan Arms conversion block through Optics planet and installed it with the AR15 lower (replacing the Stern). Tested it last weekend. More than 50% of the time, there is failure to eject the spent casing. Same problem with just racking. The live ammo won't eject easily. I've sent a video to Sylvan Arms service.