Solution: operate the camera upside down 🤣
But seriously, does the downstroke cock the shutter or something?
as far as I can tell, the downstroke does cock the shutter. It's really weird, because if you push the lever down, it seems nothing happens, but then if you release it very slowly (upstroke) the shutter will slowly open and stay open for a bit, until some undetermined (by me) place in the stroke occurs and the shutter snaps shut again.
It's like it has a pseudo bulb function.
If you push the shutter lever down, and then release it as normal, the shutter seems to operate as it should, with a quick, maybe 125th second time.
Very funky!