Very recently i've come across a strange problem:

Exiting the End through the End Portal does not drop you in the middle of nowhere anymore; it instead sends you out of a Nether Portal.

For me, though, I was sent to the old map and since I had no portal...it made one. Right in my house. It was also near my "home bed", which I believe is the origin of this problem. Might wanna look into this.

[edit] I also forgot: somebody managed to make it happen in waterworld as well.

tested with a bed in oldworld: got sent to my portal there which was very close.
next slept in my bed in waterworld: it spawned a portal there 3blocks or so from my bed

Well, my bed in the oldworld spawned me in the middle of nowhere, where i place my chests! And i slept in a bed, that was distroyed, and now when i come out of the end i end up in ChocolateIVIan's base, then i go through the portal, that takes me to someone's base.

Ps: if anybody finds those chests, please contact me, i have a lot of stuff in them.

I jsut get redirected to the spawn nether portal...

chang that'll be because your spawn point is set at spawn

But when I die, I spawn in the old world, where I last slept...

I teleport to my own base too.