Resetting a Bienno LiFePO4 Battery

A friend of mine was having an odd problem with his Bienno LiFePO4 battery that I had never seen before. He lent me his battery while I was working on his panel. https://www.bioennopower.com/collect...epo4-batteries

The next day I was surprised when the battery didn't power up the panel. So I measured the output voltage of the battery. It was 2Vdc! That's not a typo, it was only two volts! Very strange. I put the battery onto the appropriate Bienno branded charger (which I assume is a dumb charger).

The next day the battery was back at an appropriate 13.5Vdc. Used it a bit to test the panel then disconnected it from any load. Next day the battery was back at ~2Vdc again! Repeating the charging cycle and same deal - OK at first then 2Vdc later. Something internal to the battery seemed to be draining the battery.

The friend contacted Bienno and they replied;

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Please try the following:

1) Attach the charger to the battery. Connect the AC-to-DC charger to the AC outlet.
2) *Simultaneously* to the battery, please attached [sic] a load (12V load such as LED light, or GPS etc.). Turn on the load for 20 seconds.
3) This will force a reset of the battery.
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The friend reports that this fixed his issue. I assume this resets the battery's internal power management system which must have been draining the battery.

Anyone else seen this issue? I own two of these same batteries and have not.. Could this fault cause long term damage to the battery?

Thanks, John OHM Ω