Puffed Lipo?

[Muggydude]

I bought two new Turnigy 6s 30c 3600mah lipos. They arrived, and on one of the packs, the top cell is slightly puffed, maybe 1mm or 2mm. I charged both up fine, and both packs have all the cells read 4.19volts. On the good pack, the cells are hard. On the puffed one, the puffed cell is slightly soft, and I can push in the foil a bit, but it does sort of pop back. Is it possible they didn't fill it enough? Think it's ok? I ran them both for a few minutes and they run the same. Afterwards all the cells were 4.10 volts. It didn't swell or anything.

I mean, I'm not quite exactly sure it's even puffed. The cell isn't really swelling, but I can push it in a bit, but then it gets hard like the other cells. It's like there is the hard cell, and then some fluid and the the foil wrap stuff, which is a little big or something. It's not like it looks like it's going to burst or anything.