https://www.dropbox.com/s/ivzeweudbzgmsy7/15w36d%20render%20issue.mp4?dl=0
world generated fine, but when closed then reopened rendering went crazy.
NOTE same thing would happen in 1.7.10 with optifine and render dist. set to about 12 or so on multiplayer servers.
P.S. sorry if video quality is fuzzy, still need to adjust recording software settings.