Blocks in the overworld clone their Nether counterparts

Steps to Reproduce:

1. Create a new world (Can be reproduced more easily in a flat world);
2. Go to the Nether;
3. Die in there, while in survival mode;
4. Attempt to mine any block in the overworld after you respawn.

Observed Results:
The blocks you punch turn into nether related blocks.

Expected Results:
The blocks stay the same.

Screenshots/Videos attached: Yes

Notes: You must die in survival mode in order to easily reproduce this, otherwise you'll experience MC-175988.