Inspection and repair of AGENT GMD-500 knob/HM door knob

"The door knob is coming off."

It seems that the door knob has been removed. When I checked it, the pull-leg seemed to be tightened loosely. It looked like an HMD, but it looks like an AGENT GMD-500 universal replacement knob.

I took it apart once and reassembled it. Repair completed using retaining screw.I was surprised that it was operating until it reached this state.The standard product comes with a pull-leg screw that has been processed to prevent loosening, but when I disassembled it and checked it, it was a normal screw.