This is still occurring. It is even occurring with Tutorial 6-7 "as is" without any editing whatsoever. I played with it: the Requisition is getting updated. If you refresh the page after the error message, the selected row is updated. If you remove the "Refresh Requisition List" action, the error goes away and everything seems fine, but then you need to refresh the page to see the update. If I had to guess, the table is trying to maintain the selection while it's reloaded and it doesn't like that.
For best results, use the Firefox browser..