How do I avoid this multiplayer bug "Cannot read properties of null?"

This is what things look like for the host and the peer:

This is what the console is saying over and over:

Thanks!

Here's a .c3p file that should help illustrate what's going on. Should be pretty simple.

drive.google.com/file/d/121Gd9Txixt-Cw8cLMemnyYzNgxaUAYdU/view

Thanks!

As an update, it still happens in r285 stable.

Although I'd like to fix this, I'd also like to offer players a way to get out of the game if this happens. Right now trying to disconnect from the multiplayer room doesn't work as it should, and the next steps in the process don't fire (doesn't disconnect from signalling server etc.). Is there a condition that I could include that would capture this scenario? If so I could give players a button to just completely disconnect entirely.

In a normal playthrough, yes, the disconnect flow works as intended. It's just when this error occurs that attempting to disconnect fails.

Any chance that there are more things that I can look at in the debugger for Multiplayer? Right now when I view the Multiplayer object in the debugger it just says it's on or not, but nothing like whether you're connected to the signalling server, if you've joined the room, any packet losses, etc.

I would not hold my breath on anything official. When working on multiplayer projects, I often made my own debugging text/textbox for whatever I needed to see or figure out.