Think I found out what's happening!
Everything is probably fine. Read in Precision Circuits manual
Battery Isolation Manager Operation
The Battery Isolation Manager (BIM) monitors the Battery Voltage of both the Chassis and Coach Batteries over long periods of time. If it senses a charging voltage, it connects the two batteries together. If the charging system is drastically overburdened, the batteries will be isolated, however, if the BIM sees a long term charging of both batteries it will allow the batteries to remain connected and allow the charging system to do its job. Once the batteries have reached a Float Charge state for one hour, the BIM will isolate the batteries to prevent overcharging, and will only reconnect the batteries for charging if one of the Battery drops to approximately 80% charge, and the other is being charged. If the batteries are not being charged, BIM isolates the two batteries to prevent an electrical draw in one system from depleting the other battery. The long term monitoring of the batteries prevents the annoying Relay clicking that exists in simpler Isolation Modules today.
c. Overcharging of Coach Battery during long drives by shutting down every hour and only turning back on when Coach Battery needs charging.
Sounds like it's just the way it's designed.
2004 Winnebago Minnie 22e(went to a nice family Oct 3, 2015)
2016 Forester 2701DS (Aug 31, 2015)
2015 Camping 3 trips 6 nights
2016 Camping 9 trips 28 nights