diff --git a/client/core/src/lib/modified.js b/client/core/src/lib/modified.js
index 1b37f3af6..79f725633 100644
--- a/client/core/src/lib/modified.js
+++ b/client/core/src/lib/modified.js
@@ -5,7 +5,7 @@ export default function getModifiedData(object, objectOld) {
     var newObject = {};
     for (var k in object) {
         var val = object[k];
-        var valOld = objectOld[k];
+        var valOld = objectOld[k] === undefined ? null : objectOld[k];
 
         if (!isEqual(val, valOld)) {
             if (val instanceof Object) {