For what it’s worth, this seems to be a problem across an LXC mount bind as well. I have sonarr and nzbget running on the same container, Nzbget download directory and sonarr destination directory both bound to same physical hard disk on the host, and still getting random truncating errors. As far as I know, no CIFS/smb involved. That’s not to say that I’m not getting random truncation on a remote folder as well (I am–an old series on a NAS I was/am using before upgrading storage on local machine.)