Managed to break the day-night cycle
Not that anybody's gonna read this in the near future (at least not devs), but I managed to break the day-night cycle by setting the day duration to 1 minute as a Medieval Master and then playing around a bit with the other sliders. First all goes as normal, but after a few nights, the sky won't change to day, but remains a spinning night sky. The same works vice versa. The light changes though, only the sky box seems to be affected.
This is not a matter of latitude either, I tried this in Levos, not too far from the equator.