I had one pack that did that and my charger fixed it.
Put it on NIMH charge mode for 1-2 mins then change it back to Lipo charge mode. I had a bad pack and this fixed my battery.
Also cycling it a few times might also help bring it back to life.
That same Lipo wouldnt go past 8.0 now it's going to 8.20 volts.
Now if I can just get it to go to 8.40 like my good packs I'll be ok.