The coupler does not seem to work with an aero precision 308 upper - Hogue AR-10 DPMS Thread Long Free Float Forend Coupler Only

The coupler I initially received and the new one I got after RMAing the first one both refused to continue to be threaded onto the receiver after having been tightened about halfway. The coupler was lubricated and tightened with a strap wrench to the same halfway point. It got to the point that I feared actually damaging my receiver by trying to make the coupler thread any further. I have no idea if I just simply got two badly threaded items in a row or the coupler's simply don't like Aero Precision uppers. I know the receiver itself is fine as I was able to reattach my Guntech handguard with no issues.