Some users may have received "push failed" notifications for files that were in fact delivered successfully. In some cases the push was then retried automatically. If the destination is set not to overwrite existing files, the retry also produced an "overwrite existing" error.
You can safely ignore these notifications. The files reached their destination without any problems, and no action is needed on your side.
We have deployed a fix and are monitoring the results. We apologize for the confusion this may have caused.