I wonder what could cause the behavior?
3.3V is not much. My S110 switches off at 3.2V.
In the moment, where the lens goes out, the camera needs a lot of current. In this moment, I would think, the power goes a little bit down and the cam switches off.
I don’t think that is a problem of the DC coupler.
In the past I have used a Canon DC coupler DC-10, but would like to drop it. Or is there some circuitry inside the DC coupler I am not aware of?
My DC supply delivers more than 4V