Opinion bubble while visiting other cities

This seems to happen to me only on every last day of the CoM. I think that maybe they are doing this in response to players complaining that their valuable storage space, especially during the final hours of the CoM, was being taken up, (maybe annoyingly so), by 4 metal, 5 minerals, 3.plastic, etc., from one single place visited. I noticed today that after completing all of my CoM assignments, the bubbles re-appeared when visiting other cities.