Are you making the edit by selecting the graphic frame and then choosing Edit Original? This will always auto-update.
If that's not it, you might try clicking Preferences > General > Reset All Warning Dialogs
That's it! We use the Xinet plug-in for our server. The users this was happening to had the issue above. When we install the plug-in we 'lose' the Edit Original feature and it says "Edit High-Res" which is our preferred behavior. Thanks, Tom!