diff --git a/module/common/model.php b/module/common/model.php
index 99208a93d4..f0ab31e1d2 100644
--- a/module/common/model.php
+++ b/module/common/model.php
@@ -2150,11 +2150,11 @@ EOF;
             {
                 if($config->edition != 'open' && isset($dateFields[$key])) $old->$key = formatTime($old->$key);
 
-                if($value != stripslashes($old->$key))
+                if($value != stripslashes((string)$old->$key))
                 {
                     $diff = '';
-                    if(substr_count($value, "\n") > 1     or
-                        substr_count($old->$key, "\n") > 1 or
+                    if(substr_count((string)$value, "\n") > 1     or
+                        substr_count((string)$old->$key, "\n") > 1 or
                         strpos('name,title,desc,spec,steps,content,digest,verify,report,definition,analysis,summary,prevention,resolution,outline,schedule,minutes', strtolower($key)) !== false)
                     {
                         $diff = commonModel::diff($old->$key, $value);