I've been transferring (25+) TBs of files over the last week and this is my first time encountering this error.
Was initially using MC in terminal to transfer, and had 5 random files fail in transfer on this last job.
In testing, in terminal itself (not in MC), I was able to easily copy files to various directories on the same drive. As soon as I attempted to copy to a different drive, copy failed again.
Archived failed files individually in tar.gz, and moved to separate drives with no issue.
Maybe this info helps someone else