Need to clone the object before removing $-prefixed variables. Otherwise we are modifying the same data as the views are using

src/Umbraco.Web.UI.Client/src/common/interceptors/donotpostdollarvariablesrequest.interceptor.js

@@ -26,7 +26,9 @@
             //dealing with requests:
             'request': function(config) {
                 if(config.method === "POST"){
-                    transform(config.data);
+                    var clone = angular.copy(config);
+                    transform(clone.data);
+                    return clone;
                 }
                 
                 return config;