diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index e3e376e287..1670a90a5f 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -2331,6 +2331,12 @@ function group_set_user_default($group_id, $user_id_ary, $group_attributes = fal
 				continue;
 			}
 
+			// Do not update the rank if it is set to "user default"
+			if (strpos($attribute, 'group_rank') === 0 && !$group_attributes[$attribute])
+			{
+				continue;
+			}
+
 			settype($group_attributes[$attribute], $type);
 			$sql_ary[str_replace('group_', 'user_', $attribute)] = $group_attributes[$attribute];
 		}