In my survival world I only have two portals: my overworld portal right below my house, and the nether counterpart right in front of my nether mining base.

I always travel from one to the other without problem, but since I updated to 1.16.3 yesterday, the nether portal doesn't bring me to my overworld portal; instead, it creates a new overworld portal a few chunks away in the middle of the ocean.

I can still use the overworld portal to get to the nether one, but going back through the nether one takes me to this new portal in the ocean. I tried breaking the new one and trying again but it didn't work.

It's worth noting that the world was created in 1.15.1 and the nether portals were created in that version and worked as intended. I updated to 1.16 and 1.16.1 without problems in either version. This problem only started happening after I updated to 1.16.3.

Also worth noting is that I deleted the DIM-1 directory when I updated to 1.16, but again, it worked perfectly there and in 1.16.1, it only failed on 1.16.3 starting yesterday.

Other than the long swim and walk back home, it's harmless, but very annoying.