Nether portals won't generate in the Nether

When you go through a Nether portal, it will not create a return portal to the overworld.

What I expected to happen:
The system will check if there is enough free space for the portal to be created, and will generate a portal there if true.

What actually happened:
You will be spawned directly relative to your position in the overworld, even if it is in solid blocks. Also, the portal doesn't generate.

How to reproduce:
Simply build a portal and go through it