"callbacks must be a valid uri" when using package name with underscore

The app’s android package name is:

com.my_app.local://dev-aprmp-moretonblue.au.auth0.com/android/com.my_app.local/callback

notice that there’s an underscore in there, but when I do:

com.myapp.local://dev-aprmp-moretonblue.au.auth0.com/android/com.my_app.local/callback

it becomes valid. Notice that there is still an underscore on the second occurence of the package name, but not in first occurence.

I think this is a bug.