Me too.. have yet to hear a straight answer. The only pattern I've seen is heat or left a full charge. The full charge I've heard is the water expands an puff verse heat ruins them so a puff is not all puffs
. Me I got some that puffed for no reason all my batts are treated the same. I got some 1300mAH that were given to me , they were so bloated you could bounce them but they work they same as others??? So since I know mine were not miss treated I use them the same as non puffed aka charge in bag, store at 3.85V charge before fly an discharge to 3.85V after if not used.
Got some 3 years old still good an some 1 year an puffed ??? So all in all it's the battery aka manufacture an time of day
Rich