entering the nether quickly after exiting crashes the game and kills you instantly, to add to this your inventory appears to be unrecoverable as it seems to kill you far from the portal, there is no picture I could use to visualise this bug, but it borders on game breaking given the possible losses. I can reproduce the bug by entering the nether then exiting then entering immediately after exiting

I would also like to note that experimental gameplay was set to on, so this could relate to that.

edit 12/28/2018: I was able to recover the lost items, they were in the overworld near the portal I entered, but they were a bit of a ways away from it, I think they weren't even in the same chunk, this does help alleviate the feeling of having lost valuable items at least. the strange thing is that I distinctly recall the death screen showing me in the nether, but maybe I am misremembering.