My server has been pretty active for quite a while now, maybe a few weeks to a month, and we've recently had an issue with the day/night cycle. I'm not sure exactly what the problem is, or how to fix it, but here's what we've experienced:
the sun will move in the sky normally until it gets to the point where it's supposed to begin setting. Then, it will teleport back to the other side and become morning again, skipping the night completely. I can still use commands to set it to night time and the night will pass normally, with the sun rising as it should, but once that night passes, it will go back to skipping the night. This is great for not having to deal with phantoms, but not great for playing average survival minecraft. The only problem I can see is how frequently it rains, and that bedrock players cannot see the rain, but other than that the server is completely normal.