Are you guys sure? I have 17 days in a row. Assuming the counter is set to register a day if a user is logged in during a specific period and not 24 hours from the last login, and if you're in a weird time-zone, where it registers this at, say, 4pm your time, it would be easy to log in at 3pm one day, and then 5pm the next, and you would essentially lose your consecutive days.
Just sayin'. :) I have no idea what method they've used to count days, but theoretically this could happen.