LG G4 battery

I normally have an extended life battery in my LG G4 but needed to go back to the original battery for a short time .
I installed the original and the phone and battery were fine for a couple of days when the back cover popped of seemingly for no reason but I couldn't snap it back on.

Upon further inspection , I noticed the original battery was bulging on both of the long flat sides and would no longer seat in the phone .

I'm lucky I purchased the extended life battery that Bob Proffit suggested in a different thread .
Maybe folks should inspect their batteries.