This might be the problem - from one of the VMF authors on the workshop page
We’re aware of the issue and are investigating what went wrong. This update was supposed to migrate VMF to the newest network system introduced in VT2 v1.4. VMF worked fine during the testing, and for some reason it doesn’t anymore. For now, I rolled back to older version so it won’t crash players while we’re working on a fix
It’s interesting to read that the networking backend was updated, possibly another preparation for incoming Versus unless this is something they’re just migrating to now (and also most likely related to the new host migration)