Nether portals are not linking up the way that they are supposed to

What I expected to happen was when I returned to the overworld from the nether, it would link right back to my overworld portal

What actually happened was I got teleported to a random location upon re-entering the overworld

Steps to Reproduce

1. Build a nether portal at x, 78, x (x, y, z)
2. Enter the portal
3. Re-enter the portal after arriving in the nether to go back into the overworld