Keep Inventory is broken in the Nether, but not the Overworld
What I expected to happen was...:
If you die in the Nether with the keep inventory rule on, you keep your stuff.
What actually happened was...:
You lose all your stuff in the Nether
Steps to Reproduce:
1. Do the command to turn keep inventory on
2. Go to Nether and have something on you
3. Die
Unable to reproduce, please make sure you do not have a command block or datapack constantly setting it back to "false".