I don't have a lot of experience with moving what would normally be local folders inside a profile to the NAS, but the two times I've seen it done it didn't "work 100% of the time" nor did it work "100% properly".
I don't know how to fix your issue, but I'd highly recommend you not do this. I've seen problems where the syncing from the NAS to Windows desktop, then back doesn't work 100% and files just disappear because the sync failed.