diff --git a/src/wp-includes/ms-functions.php b/src/wp-includes/ms-functions.php
index 697da4b010..3c1911a537 100644
--- a/src/wp-includes/ms-functions.php
+++ b/src/wp-includes/ms-functions.php
@@ -161,8 +161,8 @@ function add_user_to_blog( $blog_id, $user_id, $role ) {
 
 	if ( !get_user_meta($user_id, 'primary_blog', true) ) {
 		update_user_meta($user_id, 'primary_blog', $blog_id);
-		$details = get_blog_details($blog_id);
-		update_user_meta($user_id, 'source_domain', $details->domain);
+		$site = get_site( $blog_id );
+		update_user_meta( $user_id, 'source_domain', $site->domain );
 	}
 
 	$user->set_role($role);
diff --git a/tests/phpunit/tests/user/multisite.php b/tests/phpunit/tests/user/multisite.php
index 5cf885a630..698c6ffcd6 100644
--- a/tests/phpunit/tests/user/multisite.php
+++ b/tests/phpunit/tests/user/multisite.php
@@ -365,6 +365,37 @@ class Tests_Multisite_User extends WP_UnitTestCase {
 		$this->assertFalse( wpmu_delete_user( $u_obj ) );
 		$this->assertEquals( $u_obj->ID, username_exists( $u_obj->user_login ) );
 	}
+
+	/**
+	 * @ticket 38356
+	 */
+	public function test_add_user_to_blog_subscriber() {
+		$site_id = self::factory()->blog->create();
+		$user_id = self::factory()->user->create();
+
+		add_user_to_blog( $site_id, $user_id, 'subscriber' );
+
+		switch_to_blog( $site_id );
+		$user = get_user_by( 'id', $user_id );
+		restore_current_blog();
+
+		wpmu_delete_blog( $site_id );
+		wpmu_delete_user( $user_id );
+
+		$this->assertContains( 'subscriber', $user->roles );
+	}
+
+	/**
+	 * @ticket 38356
+	 */
+	public function test_add_user_to_blog_invalid_user() {
+		$site_id = self::factory()->blog->create();
+
+		$result = add_user_to_blog( 73622, $site_id, 'subscriber' );
+		wpmu_delete_blog( $site_id );
+
+		$this->assertWPError( $result );
+	}
 }
 
 endif ;