Balancing

I have a maxamps pack and the method balancer that maxamps sells andalways balance charged it. The one foolish time I ran it in a stock xl-5 stampede with no LVC, I ran it down just below 6v (2s). I freaked, charged it up above 6v with nimh charger, then finished charging on my lipo charger. Ever since that one time, it has never caused any of the cell lights on my balancer to light up. As if it's either not balancing or it's really good and balanced. I get no errors from the balancer, it fires up just fine, and just sits there not lighting up. I've probably used the pack about 4 or 5 times since. Any idea? Potentially bad? No signs of battery puffin.