Like literally inflating from pressure difference?…. or just getting a little puffy/lose from use and age? The latter is OK… 2015 was quite a while ago, in flashlight technology years.
@kramer5150 inflating from pressure difference i would say. I actually opened it up and took out the eneloops and it deflated. Could it have been the batteries? Or the Sydney weather? Which has been over 30 degrees Celsius for some time.
The EA4 had the two-stage camera shutter switch - no switch cover to balloon. There was a problem some had with early EA41s. Nitecore made a change in the switch cover material, and if I remember correctly, would send a new version of the cover to anyone who asked.
Where is your light normally stored? 30C out in the open isn’t all that hot, but if it was in an enclosed area exposed to sunlight, it would have probably gotten to the temp where air pressure would cause ballooning.