@arsenbenda Thanks for your report. At phlow we are trying to smooth things over, but few hiccups are still expected (apologies for that).
Would you be able to let us know which device are you using and which application (iOS, Android or web app)?
Also, it would be ace to understand when the 404 error happens. After you upload the physical file, or when you click “Publish” in the publish page after having set the tags?
Thanks a lot!