Issues with desync

[Shepaard]

Currently trying to play the coop campaign with a friend; the game consistently desyncs and boots one of us - have tried many things to problem solve, but it doesn't seem to help the issue.
My main suspicion as to why we consistently see desyncs, is that my friend is playing on a mac, while I am playing on windows.
I will attach logs and hopefully someone smart can figure something out.

Thanks in advance.