My wife runs her minecraft on a OMEN Gaming HP laptop. It's worked fine up until tonight. Tonight, whilst she when she created a hardcore map in single player, the game suddenly started flipping rapidly between day and night. So much so that she got nauseous and had to exit the program and shut down. I tried restarting the program and it didn't help. Uploading an image won't help, because it's either going to show day or night, depending. I checked the stats, and every time it switched between day/night, the "day" stat would change between Day 0, and Day 2.
I'm used to running on an iMac, so I have no idea how to troubleshoot on a PC. She doesn't either.