You may see this message if there is an unusual delay between clicking a button to save a change and that save being acknowledged.
Such a delay is due to congestion on the Internet between the Thoosa server and your browser. It does not indicate that data was lost but your browser may now be showing values which are out of date. Press the Reload button (F5) to show the current values.
Please note that this event is not visible to the Thoosa system so, if it persists, please raise a ticket to inform us of the issue.