Version 4.1.19.4

system/Application/Module.php

@@ -376,7 +376,9 @@ class _Module extends \IPS\Node\Model implements \IPS\Node\Permissions
 		
 		if ( $new )
 		{
-			\IPS\Db::i()->insert( 'core_permission_index', array(
+			/* There is a unique constraint against app + perm_type + perm_type_id, so we use replace() instead of insert()
+				in case there is already a row in the database for this constraint */
+			\IPS\Db::i()->replace( 'core_permission_index', array(
 					'app'			=> 'core',
 					'perm_type'		=> 'module',
 					'perm_type_id'	=> $this->id,