The default start/end dates on the breaks page don’t seem to take into account my timezone, the way the goals page does.
Compare the breaks page:
With the goal page:
Both those screenshots were taken on 2023-02-09 in my current timezone. The goal page accurately adds 7 days to that as the default break start date, but the breaks page only adds 6 days, presumably because it’s still the 15th in the server’s timezone (which perhaps is Pacific time—it’s already the 16th in UTC.)