Moves and doesn't hold zero - C&H Precision Weapons SIG Sauer P320 RX/X Series ROMEO1 Pro w/ RMR Holes Filler Plate

Had this installed on my Sig P211 with a 507 Comp for around 5000-6000 rounds. I've had to re-zero twice after my initial zero. Screws torqued to spec, and I added witness marks. No backing off, screws stayed tight. Finally pulled the plate off and found the anodizing on the bottom is wearing, indicating movement. No wonder my zero is shifting and I can't hit anything. You had one job, filler plate. This is going in the trash and I'm going to try a Calculated Kinetics next.