I’ts probably academic to even ponder why we can’t use the handle as is, but my curiosity about the origin (in case it may have been fixable somehow) took me to another thought in terms of where the issue could manifest. It could well be more plausible to envision it happening within the twisted-on plug body. In the pic you can see that the -ve spring (blue) is captive and relatively close (although apparently well shielded) to the nearby positive pad (red, 1 shown and also sprung) So these mechanical/moveable parts are quite close such that a bit of excess pressure might compress/twist the spring (which could itself have a fault/sharp-edge or be seated loose) or perhaps the shielding wasn’t moulded properly and can short within that area somehow - it seems like a busy little multifunctional part that is subject to the greatest variability of handling use in the field, has moving aspects plus needs force/twisting.
Pure speculation and pointless in any case, but from an academic interest and using a slightly more considered guess i wonder if there was some displacement of the spring either axially or rotationally such that the wiring within shorts, i.e. the tube seems less likely to be the culprit (in terms of facilitating the short) which could be a pity as the cable might have been a reworkable part - in any case there’d still be no option but to cease use given the potential realworld and PR implications. A recall is the safest/cleanest solution. It’s such a pity, it sold me on the convenience of going battery powered. This thread seems unusually quiet, i wonder what’s going down in social media channels or perhaps there just weren’t that many sold ? - i’d like them to redesign and rerelease but i’m 50/50 on that happening and i really doubt there’ll be any clues either way - now where did i put those rubber end caps, i knew i’d misplace them !?!