Zenobia C shutter mechanism

Newbie here. I inherited a Zenobia C camera with a DOC Rapid shutter from my parents. I'd like to try it out, but I'm not sure it is in working condition. I noticed that when I cock the shutter, the lever does not remain up, but instead immediately returns to its resting position, opening the shutter in the process. Does this mean the shutter mechanism is broken, or is that normal when there is no film in the camera? I've never seen this problem mentioned in any Zenobia-related forums.

The shutter needs a CLA, clean-lube-adjust.
Any lubrication has dried out and turned sticky or hard.
Repeated operation might get it working but its a long shot.