GO GO JUICE BOOMER ZOOMER MAKER
Well I am glad I never talked with you about this when it was happening.If a single cell reaches 4.2V, that doesn't neccesary mean the cell is bad.
First of all, it clearly indicates your BMS has failed and you have overcharged the cell. Thats nothing the seller of the cells can be blamed for.
If it IS a runner, the BMS should have avoided this. Once thats done, you need to do a capacity test. That would indicate whether the cell is bad (it shouldn't reach its rated capacity)
They honoured their warranty in the end.
So I am glad.
Anyhow, the point I was making is obviously missed.
Sorry I can't delete what I said if no one gets the point or any help.