I always get confused here when folks are using COACH and HOUSE names for the battery systems.
I always call the battery for the truck the START or TRUCK battery. To me its only function is to start the truck and run the truck electronic systems. I try to never tap into the truck system as that is my way to get back home haha...
Sounds like your Progressive Dynamics Charger is seeing a charged up battery...
I monitor my TRAILER batteries with a BATTERY MONITOR PANEL that reads actual DC VOLTAGES. Then there is no mistake on what the battery system is doing.

Just my thoughts
Roy Ken