Auth0 Home Blog Docs

Resource Owner Password grant while migrating users

I am setting up my initial password flows for auth0 and one requirement has me using a password grant.
I have it working for users that are new or have been migrated from our custom database. However, if I try and do it for an un-migrated user I get a username and password error.

This behaviour appears inconsistent to me.
This app can not find a user via the management API because the user doesn’t exist.
Nor can it create a user, because the email exists in getuser.js
Nor can it migrate a user, because it is using a password grant.(which apparently doesn’t call login.js)
Interestingly my ActiveDirectory users migrate using the above technique.

Is this expected behaviour?