When you create a new profile that way, it won’t have a user name attached, which causes the message you saw. Didn’t consider this case when the profile uploader got some additional safety checks recently. Thanks for the heads-up.
Have to look into that. For the time being you should be able to work around the issue by making a copy of your own profile in the config app while you are logged in and then upload the copied profile. When you copy a profile in the config app, your user name gets attached to the copy and you should be able to upload it.