GTK: "Object with ID not found" error, but the ID is empty

Question

Problem description

I am working on GTK UI in Cambalache, and I have this minimal minimal Vala code to kickstart it with no functionality yet:

public class Application : Gtk.Application {
public Application () {
    Object (application_id: "gps.correlate");
}

protected override void activate () {
    var builder = new Gtk.Builder ();
    try {
        builder.add_from_file ("gps correlate.ui");
    } catch (Error e) {
        print ("Error: %s\n", e.message);
        return;
    }

    var window = builder.get_object ("main_window") as Gtk.Window;
    if (window != null) {
        window.set_application (this);
        window.present ();
    }
}

public static int main (string[] args) {
    var app = new Application ();
    return app.run (args);
    }
}

As it can be clearly seen, I only explicitly retrieve the "main_window" from Builder. However, running the program fails with message:

$ ./simple
Error: gps correlate.ui:33:1 Object with ID  not found

The problematic line is <menu id="hamburger_menu"> in my popover menu defintion:

  <object class="GtkMenuButton">
    <property name="icon-name">open-menu-symbolic</property>
    <property name="popover">
      <object class="GtkPopoverMenu">
        <property name="menu-model">
          <menu id="hamburger_menu">
            <item>
              <attribute name="label">Settings</attribute>
            </item>
            <item>
              <attribute name="label">Strip GPS Tags</attribute>
            </item>
            <item>
              <attribute name="label">Help</attribute>
            </item>
            <item>
              <attribute name="label">About</attribute>
            </item>
          </menu>
        </property>
      </object>
    </property>
  </object>

Indeed, the error got only introduced after I attempted to add the menu model for GtkPopoverMenu. Nonetheless, I don't see how this line would be responsible, nor what could I do to fix it. As I stated earlier, the only element I explicitly retrieve is the main window, and that process doesn't fail. Moreover, this line defines the id, but the error message contains a blank spot in its place.

Additional information

I compiled the program with: valac --pkg gtk4 --pkg libadwaita-1 --pkg gio-2.0 simple.vala, my OS is Fedora 39, and the whole UI file is listed for completeness down below:

<?xml version='1.0' encoding='UTF-8'?>
<!-- Created with Cambalache 0.16.0 -->
<interface>
  <!-- interface-name gps correlate.ui -->
  <requires lib="gio" version="2.0"/>
  <requires lib="gtk" version="4.12"/>
  <requires lib="libadwaita" version="1.3"/>
  <object class="GtkWindow" id="main_window">
    <property name="title">GPS Correlate</property>
    <property name="titlebar">
      <object class="GtkHeaderBar">
        <child>
          <object class="GtkButton" id="add_images">
            <property name="icon-name">list-add-symbolic</property>
          </object>
        </child>
        <child>
          <object class="GtkButton" id="remove_images">
            <property name="icon-name">edit-delete-symbolic</property>
          </object>
        </child>
        <child>
          <object class="GtkButton" id="add_gpx">
            <property name="icon-name">mark-location-symbolic</property>
          </object>
        </child>
        <child type="end">
          <object class="GtkMenuButton">
            <property name="icon-name">open-menu-symbolic</property>
            <property name="popover">
              <object class="GtkPopoverMenu">
                <property name="menu-model">
                  <menu id="hamburger_menu">
                    <item>
                      <attribute name="label">Settings</attribute>
                    </item>
                    <item>
                      <attribute name="label">Strip GPS Tags</attribute>
                    </item>
                    <item>
                      <attribute name="label">Help</attribute>
                    </item>
                    <item>
                      <attribute name="label">About</attribute>
                    </item>
                  </menu>
                </property>
              </object>
            </property>
          </object>
        </child>
        <child type="end">
          <object class="GtkStack" id="run_abort_stack">
            <child>
              <object class="GtkButton" id="run_correlation">
                <property name="label">Run</property>
                <child>
                  <object class="GtkBox">
                    <property name="spacing">6</property>
                    <child>
                      <object class="GtkImage">
                        <property name="icon-name">media-playback-start-symbolic</property>
                      </object>
                    </child>
                    <child>
                      <object class="GtkLabel">
                        <property name="label">Run</property>
                      </object>
                    </child>
                  </object>
                </child>
              </object>
            </child>
            <child>
              <object class="GtkButton" id="abort_correlation">
                <property name="label">Run</property>
                <child>
                  <object class="GtkBox">
                    <property name="spacing">6</property>
                    <child>
                      <object class="GtkImage">
                        <property name="icon-name">media-playback-stop-symbolic</property>
                      </object>
                    </child>
                    <child>
                      <object class="GtkLabel">
                        <property name="label">Abort</property>
                      </object>
                    </child>
                  </object>
                </child>
              </object>
            </child>
          </object>
        </child>
      </object>
    </property>
    <child>
      <object class="AdwBanner" id="gpx_set">
        <property name="button-label">Remove</property>
        <property name="valign">start</property>
      </object>
    </child>
  </object>
</interface>