When developing as localhost I've had some instances where logging in did not put the window I logged in on into a logged in state, but a separate browser window did open that was logged in. The same code base never had the same behaviour within the DXP environments and to be fair I've not noticed it since 12.15.x if that helps.
I have a user assigned to a group called ServiceSupportTeam and it is mapped to CmsEditors as follows in appSettings.json
here is the startup.cs:
And when I try to login as the user at first, not able to login in and I GET returned to login screen,
then I close browser and run app again and then I can get in
sometimes the user login of a mapped role works, sometimes it doesn't. is this some cookie in play? something else I need to configure on startup.cs?