I now have one shorted group
Thanks for the advice.
My BMS balance connector is very tiny I don't have the probes to go pint pin safely.
I dismounted the cells to add a wire to reach group separately, my Bafang 12sx4p pack has 4 "pockets" with 3 groups in each pocket.
The group number 9 is now short circuit, 0.2 V with BMS connector on and off.
Other cells vary from 4.2V to 3.6V.
This was not the case last week. I am praying I am looking at the cause.
Looks like I am going to have to replace my cells.
I'll update this case later after I have new cells installed.
Hopefully I will get my 10 posts in soon and can post some real photos to this forum.