I had pressure building up my AAA twice. No flights or changes of altitude. The first time I could barely get the head unscrewed it was so tight from the pressure. The "pop" was pretty intense when it finally opened. The battery must have outgased somehow.
Me too.
Gore makes a cloth that will not pass water molecules, that can be put over the hole. There is also a ceramic that will do the same thing, and is more durable. Neither will pass straight water.
you don't have to sacrifice waterproofness to fix it. All you need is a self energizing seal, which allows a seal from one direction only. Check the tailcap seal of a Mini Maglite (only the minimag has it)
These quotes are from 2004. Does any other light have something like that these days? Maybe even a button you could press that will release pressure? My Fenix E05 has to be twisted on and off and the pressure made it feel like the seal wasn't seated correctly or the threads were wearing out, but the pop when I changed the battery made me realize it's the pressure.