When connecting to a secondary without slaveOk, Compass generates an error message as expected.
Navigating to Connect->Disconnect in the menu bar and then connecting to a legitimate Primary (or any Healthy connection), the error message persists in the content div and does not draw/write out the Compass user interface. This UI error has occurred during other error messages upon initial connection (for example, cannot list databases from admin database permissions on an Atlas M0), but this secondary test has been the most consistent example.
The content div container should be cleared and react app written to ensure a Disconnect->Connect does not persist previous connections' error messages.