diff --git a/classes/views/frm-settings/form.php b/classes/views/frm-settings/form.php
index 99ea8670d2..ecbc28b012 100644
--- a/classes/views/frm-settings/form.php
+++ b/classes/views/frm-settings/form.php
@@ -26,6 +26,7 @@
 
 					<?php require FrmAppHelper::plugin_path() . '/classes/views/shared/errors.php'; ?>
 					<input type="hidden" name="frm_action" value="process-form"/>
+					<input type="hidden" name="action" value="process-form"/>
 					<?php wp_nonce_field( 'process_form_nonce', 'process_form' ); ?>
 
 					<?php
diff --git a/tests/cypress/e2e/admin-html-validation.cy.js b/tests/cypress/e2e/admin-html-validation.cy.js
index 7fe46bfcd4..adb095ae4e 100644
--- a/tests/cypress/e2e/admin-html-validation.cy.js
+++ b/tests/cypress/e2e/admin-html-validation.cy.js
@@ -29,6 +29,8 @@ describe( 'Run some HTML validation', function() {
 		cy.visit( '/wp-admin/admin.php?page=formidable-settings' );
 		cy.get( '#wpbody-content' ).htmlvalidate( {
 			rules: {
+				// The hidden `action` field and the MCP buttons' `action` share a name on purpose.
+				'form-dup-name': 'off',
 				'element-permitted-content': 'off',
 				'valid-id': 'off',
 				'prefer-button': 'off',
diff --git a/tests/phpunit/settings/test_FrmSettingsController.php b/tests/phpunit/settings/test_FrmSettingsController.php
new file mode 100644
index 0000000000..5bf1cc7ecd
--- /dev/null
+++ b/tests/phpunit/settings/test_FrmSettingsController.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @group settings
+ */
+#[\PHPUnit\Framework\Attributes\Group( 'settings' )]
+class test_FrmSettingsController extends FrmUnitTest {
+
+	/**
+	 * Add-ons read `action` (not `frm_action`) in their Global Settings routes.
+	 * Without it, they re-render the form instead of saving.
+	 *
+	 * @covers FrmSettingsController::display_form
+	 */
+	public function test_display_form_includes_action_field_for_add_ons() {
+		wp_set_current_user( $this->factory->user->create( array( 'role' => 'administrator' ) ) );
+
+		ob_start();
+		FrmSettingsController::display_form();
+		$html = ob_get_clean();
+
+		$this->assertStringContainsString( '<input type="hidden" name="frm_action" value="process-form"/>', $html );
+		$this->assertStringContainsString( '<input type="hidden" name="action" value="process-form"/>', $html );
+	}
+}