Inconsistent consecutive days
Last night my account said "21 consecutive" This morning my account says "12 consecutive"
What's up with that?
The original consecutive day count was likely to be erroneous, as described in the bug report here. Consequently, said bug report has been fixed, so people's consecutive day counts should be more accurate now. Since your count dropped to a number besides 1, it can be concluded that yours was one of the many accounts that were affected by the original bug, so the 12 is actually the correct number.