Yes, there is a bug.
On the day in question, you had gained 200 points, but had one answer with a downvote (net rep: 198). The kicker is that you responsibly deleted this answer, which refunded the -2 from the downvote; however, the badge logic doesn't take this refund into account.
It was a known edge case, because a truly thorough check of why a user was refunded rep from a deleted post would slightly pain the database.
To fix this, we have decided to ignore all rep changes due to downvotes - whether you cast or receive them, they will no longer deduct from your daily total towards Mortarboard, Epic, and Legendary.
Expect to see 350 new Mortarboard (including yours), 6 new Epic, and 4 new Legendary badges being granted in the next day!