the threads are completely concealed by the lock ring on the button. it looks like it's past the midway point, but not all the way locked and not all the way open for super
vape mode. i wanna say give it a good turn clockwise to open it up, or see if you can back it up closed with a little might and hopefully that will loosen things up but
not strip anything. on the other hand, maybe you can get a better look at it if you take the button apart by removing the nut on the back and freeing the button top up and pull it out. then you might be able to see if the lock ring is off track or maybe caught on something. if this works and you get the lock ring off, go over the threads with vaseline or polish before you put it back on. it may just be a small burr or something in the threads of the button that has left the control ring stuck in limbo. not sure though, but you're oh so close to super vape mode.