When you save a flow the "Your flow is ready to go. We recommend you test it" message with green background appears. This message lingers if you continue to edit your flow. It should disappear once you make more changes.
Similarly, when you save a flow and try to exit without making any more changes to the your flow, the "If you leave this page, you will lose all changes since your last save." message appears. This message should only appear when you are attempting to exit with unsaved changes.