Currently the blue switch for PiP appears on Netflix previews, and overlaps with the rating controls.
If selected, it also seems to trigger a click on the preview, starting the movie. But it doesn't seem to happen all the time.
Ideally, it shouldn't be displayed on this type of content at all.
I am able to reproduce this. Doesn't seem to happen on all previews. But if you do click on the PiP for a preview, and close PiP, you could end up with a video playing in the background.