Interface takes a very long time to load when have limited access (v12.0.2)

Hello,

I have created a group “support” in my master realm and I have assigned to this group the roles (impersonation, manage-users, view-realm, view-users) on all XX-realm (x160).

I also created a user on my master realm that joined this group.

When I connect to this user the interface takes a very long time to load and sometimes I even get a 403 (even though I have the necessary roles).

For information I have no problem with the full admin account.

Do you have a hypothesis on these slowdowns?