Fenix A320 Auto Throttle not working at CRZ altitude

Fenix a320 auto throttle stops working once at the cruise altitude. Put it in CL and it just goes to max throttle and overspends, then disconnects the AP. I have tried contacting support but they completely ignored my question with their response. Does anyone know how I can manage this?

See attached Content.xml.

MS Store directory:
Steam directory:
%APPDATA%\Microsoft Flight Simulator\Content.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <Package name="fnx-aircraft-320" active="true"/>