JScript arguments concatenated on file save

Issue seen in QT creator 4.9

if a js function has multiple arguments, when saving the file the separating comma is ommited and args concatenated. eg

function myFunction(myVal1, myVal2)...

when saving it becomes :

function myFunction(myVal1myVal2)...

if the qml file is edited and saved in external editor, reloads  ok - occurs only when saving file from within QT Creator. 

If the QtQuick/QML/JS Editing "enable autoformat on file save" option is deselected saves ok.