Renders weapon useless when installed. - True Precision M/P Shield 9mm Luger Threaded Pistol Barrel

The barrel installation and reassembly of my M&P 9 Shield Plus went smoothly until I racked the slide, and that's when the problems started. When the slide is racked, it and the barrel lock. The only way I found to get them unlocked was to either insert a loaded magazine or to put rearward pressure on the slide while putting downward pressure on the muzzle. Intentionally locking the slide, for disassembly, is a little tricky because pulling the slide back just a fraction too far will result in another lockup. I tried this process several times with the same results. I returned it and ordered a replacement, thinking maybe it was just a one off, but the results were again, the same.
I bought a Faxon barrel initially and it worked flawlessly when racking the slide but a 9mm guide rod would not pass through it, to check suppressor alignment. Needless to say I returned it and bought the True Precision barrel. Smith & Wesson hasn't shown any stock for their threaded barrels for months, so I'm at a loss for finding a barrel for now.
The Optics Planet return process was very easy to follow, thank goodness.