Thanks Steve, not overly concerned but more curious. Received this back from Ryan at Blue Sky, reply to e-mail
Hi Grayson,
It sounds like your controller is accounting for the "monthly self discharge" which is normally set to 3% for AGM batteries. The controller is able to see the input from the "shore power", so no excessive draw is reflected, but since it never completes a charge cycle, it does not consider the batteries completely full, so it applies the monthly self discharge as if the were never able to be fully charged.
The controller will automatically readjust it's estimation on the batteries state of charge (Reflecting 100%) once PV input becomes available to the controller and it completes a charge cycle (transitions from absorption to float mode).
Please let me know if I can be of further assistance either by replying to this email or contacting me directly at 760-208-2149.
Regards
Ryan