And, just like that, down the rabbit hole we go....
An R model Darne is locked closed by a rather fearsome main spring, that is pinned into the lower metal, and actually sprung into the opposite bend of what it is when it is at rest. There is a fair amount of resistance getting the little guy closed, always. The opening lever gives you enough mechanical advantage to get that task done. A Charlin sliding breech gun opens and closes without any resistance, assuming the gun hasn’t been fired-if it has, you are cocking the gun on opening, and meet that resistance.
A Darne R model isn’t like that. As you already noted, keep any of your skin out of the closing operation, as it is always painful and bloody if you try to close the gun with your hide in the workings.
I’m going to go out on a limb, and speculate there was nothing wrong with the Darne clone you saw, or, at least nothing wrong with opening and closing, other mentioned issues I haven’t reviewed.
It was just unfamiliar to you.