I have the ge z-wave 12722 and the addon switch 12723 in a 3 way wire solution.
The main switch works fine, on/off HA sees the state change.
The addon will turn the light on and off.
If you turn the light on with the addon switch, the main switch state does not update in HA (the led goes out and you here the main switch click)
If you turn the light off with the addon switch, the main switch state does not update in HA (the led comes on and you here the main switch click)
Would this be a bug in HA not picking up a code that is changing in the main switch? Granted the addon switch does not have a zwave radio in it.
Would it help to run the open zwave control panel and record pushing the aux switch?