I was just about to post about this sort of world reloading thing myself.
Last time it happened for me was back in SAB and I had thought it had been fixed since.
Video of it from way back in SAB: https://youtu.be/OjokhFRe1HE
Video of it just today in Fractal Hub: https://youtu.be/Iljfr-URMuk
980 stock using the latest drivers.