Playing survival (the world has been played on LAN before if it helps, but not when the issue occurred), I went to change my render distance (it was 8; I changed it to 11) and an entire side of me... changed to this (*see screenshots) it would seem to change places every time I moved to a different block. If I went into the area, the regular blocks, water, and other stuff was there (based on interaction), but the game was showing this in the entire direction (East, if it helps).
*Seed: -1104483913
*Coordinates: 616 63 -664
*Changing Resource Packs did not affect the problem at all.
*Restarting Minecraft seemed to fix the problem... for now, likely.
*Sorry, if there is no crash report to accompany the bug, it did not come across my mind at the time