Holga GCFN lens unscrews and comes off.

Ok...I just received my new-to-me Holga GCFN and loaded film into it. I turned the lens from mountain to single person and the lens came off! There's nothing to hold it on.
I can't believe that it's designed this way...if I turn it to single person the lens just falls off.

Can anyone clue me in on what's wrong?

Edited to add: I just fixed it. I had to press the piss out of it to get it to jump past the first thread. Someone had removed it and couldn't get it to seat again, I figured I had nothing to lose and it worked.

Congratulations, you are now a certified Holga Repair Technician.
Holga's are interesting, have fun.