Comment 1 for bug 694995

GetPublicFiles is issued only on nautilus plugin startup and is not updated afterwards therefore different nautiluses can have different idea about the current list of published files. File publishing is not in the protocol and is done via HTTP requests and I believe this is the reason why this can happen.

At the moment the workaround is to re-publish the file on another computer. The URL will be returned and it will be the same as for the original publishing attempt. So even if file is published but nautilus insists that the file is not, one can publish the file again and get the same URL.