Nah man, I think you are looking into it just a bit too much. That pack is perfectly fine from what I can see. Some batteries, like the ones that you just purchased, have a plastic piece at the end that will make it "feel" puffed, but it's not. there is going to be a little bit of air in them, that is normal. When you start to get a LOT of air in there, I'm talking the pack is starting to look round on ALL sides, then you need to think about hooking it up to an automotive headlight and draining that sucker as far down as you can get it. The pack you have, I would toss that in any plane that I have without worry.