Bad Battery ?

So I think there could be something wrong with the battery pack overall. Not sure if it's a problematic cell somewhere, or the BMS is acting up. Basically my charger keeps cycling the charge on and off.. At first I figured it was normal. It's trying to balance it, and top it off.. However, over 30 minutes later it's still doing this. Not normal. Never last that long even on my active pack. Typically 5-10 at the very most, and not all the time.

Went to try my other charger, and before I even plugged it in. The charger kept blinking red and green. Plugged the battery in anyway.. BANG! then POOF! Smoke comes poring out the charger.. I remove the cover, and it's a blown capacitor. Looks easy enough to replace though. Wonder if it had problems to begin with.

I should note/add, I've had to replace a cell twice in the exact same spot as before, as for whatever reason. The cell is almost totally dead. I only get the smallest of a reading off it. I think it was something like 0.02 volts ? Also, the pack is old. I would say around 8-9 years. That could be a factor in this as well.

yes bad battery. It looks like the bms tripped because of the low cell or the balance is bad. When the bms trips it stops current from going into the battery.
But the bms while it stops the current, it doesnt stop the charger from reading the battery. The charger still reads a battery and tries to keep charging it. Thats why it cycles back and forth, its trying to forcibly try the battery to take the amps. Some smart chargers can handle this but some cheaper chargers will keep cycling back and forth until you pull the plug.

I just replaced the bad cell though, and the charger did the same thing after I replaced it. The rest of cells gave normal readings.