We had a case this week where an application for which a user was _previously_ the coordinator received an application. Because the platform sends emails to the last coordinator to make a change to the application (https://github.com/WikipediaLibrary/TWLight/blob/master/TWLight/emails/tasks.py#L186), they received an email despite not currently being the coordinator for this partner.
We should do a check before sending this email that the coordinator we're about the email is also the _current_ coordinator.