Hi i once again opened a GE Pack…
(lower one)
inside i found 3 pairs of “different” cells (same type)
2 are at 4,18 Volts
2 are at 3,96 Volts
2 are DEAD (have been in the middle)
one looks okay - the other one like it leaked! 
should i throw (carefully) away all cells or just the 2 bad ones?
i will check that a soon as i am in the headquarters!
I had something similar to this.
Other battery had a good voltage but after testing with my hobby charger it turns out that its capacity diminished, only 300mAh :
I had a 6 cell Sony Vaio pack with Samsung ICR18650-30A that suddenly failed.
The 2 middle cells were absolute zero (no leaks), the other 4 were fine.
I suspect the BMS took them out. The pack was just over a year old, (just out of warranty). At least I got 4 very nice healthy cells out of it.
That’s usually how it goes…a cell or two in a battery pack goes bad…rendering the whole pack pretty much worthless…but a few individual cells inside might still be good