On my server, my friend and I have the same client mod set, but our configs may differ slightly.

My friend was getting crashes whenever they changed dimensions, both when dying in the nether and respawning in the overworld, and when using a nether portal.

I have no issues.

Here are logs:

nether-death-latest.log
nether-portal-latest.log

Here's the complete contents of my mods folder (sorry but I've updated some mods since then so it doesn't match the set from the logs exactly)

Fixed in v3.0.0