Unable to explicitly set GtkModelButton role

Steps to reproduce

1. Create ModelButton with a stateful action-name and a role
2. Try using the pygobject widget props attribute
3. Try using the set_property method

    def _set_profile_menu(self):
        self.profile_menu_button_label.set_label(App().session.active.profile_name)

        if len(App().session.available_profiles) > 1:
            self.profile_menu = Gtk.PopoverMenu()

            profile_box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, margin=10)
            self.profile_menu.add(profile_box)

            for profile in App().session.available_profiles:
                if profile != App().session.active.profile_name:

                    profile_menu_item = Gtk.ModelButton(
                        text=profile, role=Gtk.ButtonRole.NORMAL,
                        action_name="app.switch_profile", action_target=GLib.Variant.new_string(profile))
                    profile_menu_item.props.role = Gtk.ButtonRole.NORMAL
                    profile_menu_item.set_property('role', Gtk.ButtonRole.NORMAL)

                    profile_box.add(profile_menu_item)

            profile_box.show_all()
            self.profile_menu_button.set_popover(self.profile_menu)

Current behavior

GtkModelButton still assumes role from action-name

Expected outcome

Explicitly set role property is preserved.

Version information

• Arch Linux
• gtk3 3.22.29+4+gb485cf91b5-1
• python-gobject 3.28.1-1

Additional information

Trying to override the radio CSS node (even interactively), documented here, has no effect. Is this worthy of an additional bug report? i.e.

modelbutton radio {
  opacity: 0;
}

Workaround

I have worked around this by calling the set_property method in a realize signal handler for each button.I am not sure if this is good practice.