diff --git a/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php b/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
index bd176e0b2387a26fcf020379bbdef0a104a83b4d..1ddcd0354faa5a54d7be1fbc197c418426cbf222 100644
--- a/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
+++ b/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
@@ -326,7 +326,10 @@ class InlineEntityFormComplex extends InlineEntityFormBase implements ContainerF
       // to be referenced otherwise we set the variable to false.
       /** @var \Drupal\Core\Entity\EntityReferenceSelection\SelectionInterface $handler */
       $handler = $this->selectionManager->getInstance($options);
-      $have_multiple_existing_entities = count($handler->getReferenceableEntities(NULL, 'CONTAINS', 2)) > 1;
+      // getReferenceableEntities() groups results by bundle, so flatten before
+      // counting — otherwise a single bundle with many entities counts as 1.
+      $reference_items = $handler->getReferenceableEntities(NULL, 'CONTAINS', 2);
+      $have_multiple_existing_entities = array_sum(array_map('count', $reference_items)) > 1;
     }
     else {
       $have_multiple_existing_entities = FALSE;
diff --git a/tests/src/FunctionalJavascript/ComplexWidgetTest.php b/tests/src/FunctionalJavascript/ComplexWidgetTest.php
index a2b7ab6fc1c103a1738f2abd026142e35a84ee5d..2672a6a497188769260e35e8cfd99bd3bf813712 100644
--- a/tests/src/FunctionalJavascript/ComplexWidgetTest.php
+++ b/tests/src/FunctionalJavascript/ComplexWidgetTest.php
@@ -847,6 +847,43 @@ class ComplexWidgetTest extends InlineEntityFormTestBase {
     $this->assertTrue($this->drupalGetNodeByTitle($title5) instanceof NodeInterface, "Fifth inline entity still exists.");
   }
 
+  /**
+   * Tests the Remove button on a required single-bundle field.
+   *
+   * With one entity referenced and other referenceable entities available, the
+   * Remove button must still appear so the reference can be replaced.
+   *
+   * Regression test for #3469864: getReferenceableEntities() groups results by
+   * bundle, so a naive count of the outer array reports 1 for a single-bundle
+   * field no matter how many entities that bundle contains, which incorrectly
+   * suppressed the Remove button on required fields.
+   */
+  public function testRemoveButtonWithSingleBundleMultipleEntities() {
+    $assert_session = $this->assertSession();
+
+    // Only allow selecting existing entities — this is the branch that
+    // consults getReferenceableEntities() to decide whether the last
+    // reference on a required field can be replaced.
+    $this->updateSetting('allow_new', FALSE);
+    $this->updateSetting('allow_existing', TRUE);
+
+    // Create multiple referenceable entities in the one target bundle.
+    $referenceNodes = $this->createReferenceContent(3);
+
+    // Reference exactly one of them on the parent node, so entities_count == 1
+    // and the Remove button depends on $have_multiple_existing_entities.
+    $this->drupalCreateNode([
+      'type' => 'ief_test_complex',
+      'title' => 'Single ref parent',
+      'multi' => [reset($referenceNodes)],
+    ]);
+    $parent_node = $this->drupalGetNodeByTitle('Single ref parent');
+
+    $this->drupalGet('node/' . $parent_node->id() . '/edit');
+    $assert_session->elementsCount('css', 'tr.ief-row-entity', 1);
+    $assert_session->elementExists('xpath', '(//input[@value="Remove"])[1]');
+  }
+
   /**
    * Checks that nested IEF entity references can be edited and saved.
    *