diff -ura upload/include/class.ostsession.php upload/include/class.ostsession.php
--- upload/include/class.ostsession.php	2019-01-27 19:01:42.000000000 +1100
+++ upload/include/class.ostsession.php	2019-01-27 19:14:41.000000000 +1100
@@ -190,6 +190,7 @@
         }
         catch (DoesNotExist $e) {
             $this->data = new SessionData(['session_id' => $id]);
+            $this->data->session_data = "";
         }
         catch (OrmException $e) {
             return false;