diff --git a/tests/WP_Ultimo/SSO/SSO_Coverage_Test.php b/tests/WP_Ultimo/SSO/SSO_Coverage_Test.php
index 9cf8821d..e13293e9 100644
--- a/tests/WP_Ultimo/SSO/SSO_Coverage_Test.php
+++ b/tests/WP_Ultimo/SSO/SSO_Coverage_Test.php
@@ -33,6 +33,16 @@ protected function setUp(): void {
 
 		add_filter('wu_sso_enabled', '__return_true');
 
+		/*
+		 * This test class removes temporary redirect-host filters after each test.
+		 * Re-register the production mapping callback because its singleton can
+		 * already exist when a subsequent test starts.
+		 */
+		if (class_exists('\WP_Ultimo\Domain_Mapping')) {
+			$domain_mapping = \WP_Ultimo\Domain_Mapping::get_instance();
+			add_filter('allowed_redirect_hosts', [$domain_mapping, 'allow_network_redirect_hosts'], 20, 2);
+		}
+
 		add_filter(
 			'wu_sso_salt',
 			function () {
@@ -2239,7 +2249,7 @@ public function test_startup_loads_domain_mapping_redirect_host_filter(): void {
 		wp_cache_delete('domain:www.' . $domain_name, 'domain_mappings');
 
 		try {
-			$sso->startup();
+			$sso->init();
 
 			$result = apply_filters('allowed_redirect_hosts', ['mygratis.site'], strtoupper($domain_name));
 
diff --git a/tests/WP_Ultimo/SSO/SSO_Extended_Test.php b/tests/WP_Ultimo/SSO/SSO_Extended_Test.php
index 84970add..9ac28ec8 100644
--- a/tests/WP_Ultimo/SSO/SSO_Extended_Test.php
+++ b/tests/WP_Ultimo/SSO/SSO_Extended_Test.php
@@ -1644,12 +1644,20 @@ public function test_is_enabled_source_uses_apply_filters_deprecated_for_mercato
 	 * Test get_setting returns true for enable_sso when set.
 	 */
 	public function test_get_setting_returns_true_for_enable_sso(): void {
-		$sso    = SSO::get_instance();
-		$result = $sso->get_setting('enable_sso', true);
+		$previous_enable_sso = wu_get_setting('enable_sso', false);
+
+		wu_save_setting('enable_sso', true);
 
-		// WordPress stores checkbox-like settings as scalars such as '1';
-		// SSO treats enable_sso via normal option truthiness.
-		$this->assertTrue(wu_string_to_bool($result));
+		try {
+			$sso    = SSO::get_instance();
+			$result = $sso->get_setting('enable_sso');
+
+			// WordPress stores checkbox-like settings as scalars such as '1';
+			// SSO treats enable_sso via normal option truthiness.
+			$this->assertTrue(wu_string_to_bool($result));
+		} finally {
+			wu_save_setting('enable_sso', $previous_enable_sso);
+		}
 	}
 
 	// ------------------------------------------------------------------