I think the issue is that I'm copying from /watch to /output. I made another volume called /storage that goes to /Downloads and them from there navigated to the /completed and /cleaned folders for input and output respectively and it moved them instantly.

Late to the party but I'm having the same issue. Yes, in my case both file paths are on the same file system. I'm moving from "/watch" to "/output" in Docker or "/Downloads/completed" to "/Downloads/cleaned" on the host and it is taking as long as it would to ...