@Paul-Catt Hello, have you tried force stopping the app and restarting it? (not a solution just a workaround), it seems the same behaviour as this: https://community.fitbit.com/t5/Android-App/Bug-report-Fitbit-App-stops-displaying-EOV-and-Profile-i...
Forcing the app to stop and then restarting it got the cardio fitness estimate and the estimated oxygen variation info back. Memory overflow or something like that.