SURT6000XLT keeps failing new battery packs...

[BillP]

I have three identically configured SURT6000XLT ups units.
These are new, old-stock units placed into service for the first time about a month ago.

I have installed new battery packs a few times, and each time I get these to 100% (24 hour charge), when I press the "1" power button, they pass the test initially, but any further attempts to test or calibrate results in a failed battery light and alarm.

The battery charge indicator flashes with just the one bottom LED lit.

I have tested each battery out of the UPS several times with my meter, waiting about 10 minutes between tests.
Each time I get full voltage from them.

I also opened the units and tested each battery with a load tester set to test each battery based on the specifications of each.
(I have the datasheets on all these and made sure that the tester was set right.)

Each individual battery comes back 100% healthy.

I've never seen this behavior before, and it's driving me nuts!

Is there some calibration process that I need to perform to reset these and/or clear up bad info in them?
Is there something these units have "learned" that they need to unlearn for this problem to go away?