Ryobi Battery Lockout Problem

[VK3YNV]

Ryobi Batteries have software that can kill the battery locking it out from charging and outputting power.

 

[VK3ELV]

My bother-in-law recently gave me a dead Bosch battery to look at, it appears the same a Makita with a different connector. One pair of cells were 0 volts and the rest were about 3.9 volts. I thought, well that is 2 dead cells I wonder if I have got something close enough that will balance? I manually recharged them and their brothers to 100% ( well 4.15 Volts just to be safe). To my surprise the pack has worked fine for him since over many cycles and behaves as the other packs. How did they get to 0 volts? A BMS processor hiccup? Shouldn't they be permanently damaged below 2 volts?