I've added some additional debugging for the MP issues. If you get a chance to try it again, I'd appreciate a copy of your log afterwards, as that should help me narrow down the issue. Are you able to send them via Discord DM?
There's also a console debugging command which will also provide me with additional information 'drMFStatus' - if you're able to run that on an MP session and send me the log, that should give me the information I need to fix it.