I updated a world of mine, that was created on 1.13.x and updated always on mayjor releases or pre-releases.

When I first entered the world it was all rendering stange from a distance of me. When I got to the level everithing was looking very strange. I'm 100% sure that this was not a texture pack because i did not have any instaled on this computer.

The Bug is when you look to every block naturaly generated or placed by you it will render like I've mentioned.