Martin von Gagern wrote:
> https://bugs.gentoo.org/show_bug.cgi?id=189627

Posted some more info there. Keep an eye on that page.

To me the cause seems clear: backup-buffer-copy catches and discards the
file-error caused by delete-file, probably assuming it is due to a
non-existing backup file. Perhaps the file should only be deleted if it
does really exist, and any error to delete it be taken serious.

There are some people who have not been able to reproduce the issue.
Reason unknown so far, but have a look at the bug report for updates.

Greetings,
 Martin von Gagern