When my friends and I were recording a 1.9 lets play series we went to the nether, but when they tried to get into the nether their screen read: "download terrain" and they lost half a heart from suffocating while entering. Then before the downloading terrain could finish they were sent back to the over-world downloading terrain. Then they were sent back and stuck in an infinite loop. When I tried kicking them to see if re logging would work, they spawned in the world spawn instead of near the portal or near their bed spawn. Here is the snippet from episode 6 that includes the Nether portal issue: https://www.youtube.com/watch?v=nLU1ONn9pi4&feature=youtu.be