When your spawnpoint in the nether gets obstructed, you get sent to the overworld and when you left-click the ground in survival mode, the block your looking at turns into the block at those coordinates in the nether. To fix it, you have to rejoin the game or

Expected result:

You should be able to mine blocks like normal in survival mode when this happens.

Actual result:

You can't mine any blocks because they get changed to nether blocks at the coordinates of the block that you mined.

How to reproduce:

1. Go to the nether
2. Type in "/spawnpoint"
3. Fill in your spawnpoint with any block
4. Switch to survival mode
5. Type in "/kill @s"
6. Punch the ground and the block you punched should torn to netherrack, or air

This can affect the game because you will have to rejoin the game or kill yourself again to fix it.