I was playing on a Survival server with my friends with keepInventory set to true, but when we die in the Nether, we lose our inventory, unlike the Overworld. 

What I expected to happen was...:

I thought I would have kept my inventory.

What actually happened was...:

I didn't. I  have tried seeing it will work multiple times on the server, and I do not keep my inventory.

Steps to Reproduce:

1. Join a laggy server on the server-side/make it laggy
2. enable keepInventory
3. Get some items

4. Go to the Nether and hop into the lava.

Here is a picture of F3: