We found the root cause: the authenticated user had no roles (the one coming from the IDP were wrong and could not be retrieved and set in the app).
As the authenticated user had no role the navigation used the default home page. In our case a microflow to define wich authentication page to show.
However, said microflow is only accessible for anonymous user. So the systems keeps redirecting or trying to create a anonymous user every 10 seconds (we think but are not sure, but its is our educated guess).
Set a correct user role and it should work ;)
In account entity->access rules->Administrator , check whether the checkbox(Allow creating object) is checked.