I did a bug search for this and did not see any reports of this.

Affected versions: 1.19.69 to 1.19.71 (probably other versions too)

Steps to Reproduce:

Have player 1 join a realm server.
Have additional split-screen players join. (we will have 2 to 4 players total)
Have any player select "Save and exit" from the menu.
All players are immediately disconnected from the realm and a disconnect message appears.

Message: Disconnected from server.

Reproducible 100% of the time.

I expect this behavior when player 1 chooses to save and exit. I do not expect this when players 2, 3, or 4 select "save and exit".