BC6 - Have I killed It?

[DaveG28]

Managed to muck up earlier tonight connecting a battery to my bc6 and got sparks/smoke as my reward, plus a dead BC6. However, 5 mind later it woke back up so I thought all good. I then charged my 2S cells fine at 4.2A.

However, just put a 4s on to charge at 5A and have noticed it's only balance charging at 3.3A, not 5A?? The cells are balanced and well under 4.2V each so wondered if it's normal for it to charge at too low a rate when on 4S?? Or is it damage from my cockup???

Should I try my tp charger instead?