I think what has been quietly missed in all of this is that the AUH is not compatible with the factory RotaFlex pin box. Anderson themselves have a list of pin boxes and whether they are compatible, or in many cases what accessories are needed in order for them to work properly.
In the case of the OP, this is what you need:
https://andersenhitches.com/products...ex-lockout-kit
The above kit is specifically designed to solve the issues you are having, and to prevent damage to the pinbox and/or the hitch.
hth,
Brad