Apparently I encountered a rare bug.
It occurs when you use any type of weapon that uses ammunition.
If you fire the last shell and at the same moment get caught in the net, then as soon as you free yourself from it, you will return to the same weapon, but empty. And if you try to shoot, the weapon will be in the shot status (first frame of shooting), but since there is no ammunition, it will not fire, and you will not be able to change the weapon to something else.

So far this has only happened to me once. But it’s possible that I’m not the only one who encountered such a bug.