I’ve never seen lights like that, I imagine that translucent plastic is simply to let daylight in. Probably switched out the front door at one point and couldn’t find one the exact width so got a narrower one, filling in the gaps with that translucent material. I wouldn’t think the switch would have anything to do with it. Sometimes people just remove a light and don’t want to bother taking out the wire and switch and changing the box and patching the drywall.
It’s unfortunate that the writers didn’t plan this beforehand, so we could have had some foreshadowing a few episodes beforehand with a first meeting between the two where pelia acts a little weird (because she remembers her from 200 years ago).