Fix warning, Invalid argument supplied for foreach in VARIABLES

workflow/engine/src/ProcessMaker/BusinessModel/Variable.php

@@ -564,7 +564,7 @@ class Variable
 
                 $contentDecode = json_decode($row["DYN_CONTENT"], true);
                 $content = $contentDecode['items'][0]['items'];
-
+                if (is_array($content)) {
                     foreach ($content as $key => $value) {
                         if (isset($value[0]["variable"])) {
                             $criteria = new \Criteria("workflow");
@@ -582,6 +582,7 @@ class Variable
                         }
                     }
                 }
+            }
 
         } catch (\Exception $e) {
             throw $e;