Group roles with "Scoped: Insiders" do not appear when adding a user to a group (only Individual roles visible)

I am using Drupal 11 with Group module (version 3.3.5).
I created several group roles with the visibility setting “Scoped: Insiders (can be assigned to members inside this group)”.

However, when I try to add a user to the group through:

Group → Members → Add Group Membership

the role selection dropdown only shows roles marked as “Individual”.
All roles configured as “Insiders” are missing and cannot be assigned.

What I have checked / confirmed:

The user has the global role Authenticated.

Each group role is properly created and enabled.

The roles have correct permissions to view content.

Cache cleared multiple times.

I tried recreating groups and roles – same issue.

No custom code affecting the behavior.

According to documentation and past issues, Insider roles should appear in the membership form.

Expected behavior:

When adding a user to a group, the form should display all group roles valid for members, including roles with visibility “Insiders”, not only Individual roles.

Actual behavior:

Only roles with visibility = Individual appear in the Add Membership form.
All Insider-scoped roles are missing, so they cannot be assigned through the UI.

Additional notes:

I found similar reports:

https://www.drupal.org/project/group/issues/3488619

https://www.drupal.org/project/group/issues/3456864

This issue makes it impossible to manage member roles normally and forces the use of Individual roles, which breaks access control (Node Access overrides Group access).

Environment:

Drupal: 11.2.2

Group: 3.3.5

PHP: 8.3.27

No custom modules affecting access or membership forms.