That naming convention is used by many Windows programs (edge, explorer) when you try to copy a file to a target folder and there’s already a file there with the same name.
I have never seen Hugo itself to behave like that… It either overwrites/recreates the file or complains about permissions.
My educated guess is, that you have something around the Hugo build that produces that behavior.
Following Requesting Help - Let us see your Code you should provide more details on your setup
- share your (or a reproducible) repo
- output of
hugo env - anything happening around the bare
hugocall- Theme involved
- some custom build scripts
- …
a first try could be to remove the public folder completely and retry a build