I tried to log onto a server whilst it was restarting the clicked another server and logged onto that, when the first server restarted, every block went invisible and the sun and moon started glitching.
Like here: https://www.youtube.com/watch?v=GiuySJ9j4bM&feature=youtu.be

i then relogged and the issue happened again, after restarting this was fixed.

Items in video are from Bapcraft but the world is ReCrafted Civilizations.