My Hobbyking Zippy 4s1p-4200mAh just went puffy on cell #1. I saw it and and brought it to last weekends sota (FT-817 + 25W VHF PA). I had one of those beepers but when I saw one cell went to 2,5V (others were on 3,1V then) it was just seconds after it showed 0,7V. Pack was 22 months old. I recharged it later and discharged it the same day. I got around 3 Ah out of the pack. So one cell lost a bit more than 1 Ah. I will (of course) not trust this pack and will bin it shortly. I have also received a brand new puffy 3 Ah 3S LiPo from hobbyking. After an email I got a working one but this one is now also puffed. I am not a big fan of pouch cells, I prefer 18650s (3S for the 817) or 32650 for LiFePo4. I just ordered 4 of them: https://ebay.us/zbnu8l as the Hobbyking ones are out of stock.