I created a world specifically to play with a friend. He and I have both been on it a lot. After a while he was suddenly unable to rejoin that world. Every time he joined it, within a few minutes we would encounter a strange issue. I, the host, saw his character freeze in place (If he was running at the time his character would run in place). He was able to move around and continue playing the game as normal, and even saw my character moving as normal. His game would then not load new areas of the map when he would travel, making him unable to move very far, and whenever he would disconnect and reconnect to the world, he would be sent back to where he was before the issue occurred. Anything he picked up during that time would be lost and he would be in the game for less than five minutes before it happened again. I have had 2 people other than this person join on this world, and one of them had the same issue, while the other didn't have any problems at all.