Re-auth code loads dashboard in popup

My session timed out and the re-auth window popped up. I logged in again. The popup window didn’t close. Instead the dashboard was loaded in the popup and the original page was visible behind (through the semi-transparent window). I have a screen print but there seems to be no way of attaching here. A link to the site will be no use. This is an upgrade from 392, not a fresh install.