In the context of OpenID, Cognito generates a username for SAML providers using the schema {provider}_{email}, for example google_john.doe@gmail.com. This prevent the creation of the user in Discourse as @ is not a valid character for user names. There is any way to bypass this limitation, probably just for OpenID users?
Iām not quite sure, but I think the solution is to either configure cognito to use a different username or to instead use the cognito preferred_username as the discourse username.
Solved! I have upgraded to 2.7.0.beta5 and works as expected. This means that my theory was not correct, the problem was elsewhere and is now gone. Thanks.