So i deleted everything and started a new server, running 1.10pre2 and then updated to 1.10. Everything was running fine until we built a nether portal for the first time in that world. When we entered the portal, there was nothing, everything was black, and so we thought it was still loading, but then me and my friend both hit the ground too hard and died. I decided to investigate in creative mode. Upon entering the portal(in the overworld), it spawns us at Y~2738 in the nether,, a couple thousand blocks above the bedrock roof of the nether. It doesn't even generate a nether portal, we just pop up out of nowhere and start falling. I then land on the roof of the nether in the same XZ coordinates and create a nether portal to see if it would link with the portal in the overworld, but it didn't, it took me somewhere 7k blocks away from the overworld portal, and no generated portal again, we just pop up 14k blocks up in the sky.