After creating and entering a nether portal in the attached world, I got a black screen. When I saved and reopened the game, the screen was full of netherrack in extreme close-up, and I started taking suffocation damage. The world folder is attached; it was compressed and split with 7zip.
Related issues
Attachments
Comments
migrated
Also, if I use MCEdit to create a portal frame in the Nether and then enter the game to light and enter it, I likewise land in solid stone in the Overworld. Testing with a Creative-mode world shows that if I build both ends of the portal manually, they work fine (although this wouldn't work as an updated Survival game mechanic, since entering the Nether for the first time sometimes puts me in midair above lava).
MC-61823 is related to this, I just posted there, should have searched from bottom.