Thanks everyone. Lumaforge is working with Apple on this. Fortunately we can still read/write to the SMB share in the Finder just fine, so we'll be copying all assets to an external SSD to work off until this is resolved.
Thanks Jeremy G. Thats great news. I've been working with SNS since the beginning and have been diligent about trying to solve this. They are working on a Mojave patch now and will let me know. Fingers crossed.
Wow, thanks to everyone for troubleshooting this! I thought we were all going crazy. Every once in a while we would have a disconnection, or the library refused to save. Our storage is connected through SMB. I THINK we mitigated the problem somewhat by pointing to the cache to a different subfolder whenever we switched machines.
It's crazy because Apple has broken SMB several times over the years, and they often don't communicate how they're changing the implementation. Whoever's in charge of this needs to be fired.
I am not an IT engineer, I repeat what our techies are saying. But it has something to do with port usage and netbios. Just like SNS, our support team has released a patch for our clients. I am sure that Qnap will do the same soon.