Prismatic EVE230Ah Cell squeezed and concave stud after top balancing !

[LaFabrik]

Hello guys,
in the last batch of EVE230Ah cells, i have a problem with one cells.
As always, i started a top balancing (PowerPaulAustralia method, charge with the BMS to 3,6V with the 5A active balancer)
Before the top balance the cell was perfect, same as the other cells, and after the charging the cell is now concave !
What do think ?

 

[rhino]

Looks like that cell bloated some and the non-flexible busbar would have caved in the top like that when the middle of it started to push against the cell next to it. Was there BMS attached preventing cells from going over 3.65 when charging?

Edit: see you said there was BMS, have you manually checked the voltage of the cell?

 

[LaFabrik]

Yes BMS was attached, and the voltage never gone over 3.60V
i ever top balanced many cells (i build batteries) this is the first time happen
i really don't like this