I actually have yet to be able to play this mission without running into the bug. More often than not, whoever isn't host, ends up with their game completely frozen - but oddly enough is still able to look around. The host on the other hand, has seemingly no issues. However, this last time my sister and I tried it, we thought it had been fixed at first - only to realize our games were completely out of sync. For example, screwing around, I killed her for her shotgun - but she showed zero reaction to it. She's talking like she's still alive. Then not long after, claims to have seen a grunt kill me. Lo and behold, I'm still alive and well, her shotgun still in my hands. That has to be the most bizarre case I've run into with it. But I'm at a loss as to what causes this, or if there's even anything I can do to fix it. I've made triple sure that we both had ALL the files we needed. Pretty sure we couldn't even get as far as we did without them lol