Yes that's right.
No wind, so no tension.
The line goes from the winch to the sail or boom, nothing in between. so if there's no wind to provide the tension, it's all slack.
No photo's yet as it's all a bit black in there...
There is a sort of 'cap' with two slots in it, that goes over the winch drum, the lines coming out through the slots.
The cap is a tight fit on the drum, and I guess it's supposed to stop the line getting tangled.
But not only is it too tight, so the servo often stays under power and 'dithering' when not winding, it doesn't seem to do much good on the tangle front.
As you say, it needs tension on the lines. But you only get that with a bit of wind.