Override Master Items Displaces items on page (Javascript)

Hi,

I am trying to override all items in master pages using the follownig script:

function OverrideMasterItems() {
  var allItems = myDocument.pages[CurrentPage].appliedMaster.pageItems.everyItem().getElements();
  for(var i=0;i<allItems.length;i++){
    try{allItems[i].override(myDocument.pages[CurrentPage])}
    catch(e){}
  }
}

(thanks to Harbs fro providing this in another thread)

The problem I have is that once the script has run, all items move on the page. For example a text bos that in the master has coordinates of 0 and 1p6 ends up at 26p3 and 19p6

I'm probably over looking some really obvious settign somewhere but I just can't figure out what.

Working with CS6 and Javascript on a Mac

Thanks for any suggestions