[lincpimp]

Cells do not have to puff, they can slowly lose voltage and not puff. You can try a very slow charge on that cell using the balance wires. You may have to use a nimh setting, then swap over to a lipo setting when the voltage goes over 3v. Do not use more than .10amp and do not leave it unattended during the nimh charge. I have revived a few low voltage cells this way, but what Brian says about the cell not being as good as the others may well be true.