Created date uses UTC but scheduled, started, and completed use the site's timezone
Here's a screenshot of me creating a test mailing and scheduling it for immediately sending.
The created date displays UTC but the scheduled date displays the site timezone. In the db they are stored like this:
In the database if I set SET GLOBAL time_zone = '-04:00';
then the two dates match in the Mailings list.
Though oddly enough, both dates are saved in UTC:
Proposal: we should fix the created date so that it respects the site's timezone (like the date fields). I can't figure out if this should be done with the timestamp set or when displaying.