Background process dying when I logout / nohup socat

I'm trying to start a "socat" process in the background and keep it running on my Tomato router (with Entware-NG), but it keeps dying when I logout, even though I start it with "nohup."

For example:

I can run the same thing on a CentOS server, and it stays running after I logout, but on my Tomato router it gets killed.

I tried running a sleep command:

...and logging out, and it kept...

Background process dying when I logout / nohup socat