No, I did not. So I doubt it was manually flagged before travel.

And I'll second those who say that an FLL agent caused this is pure speculation. There's no easy way of knowing, and I just threw FLL out there after someone suggested a DL agent along the trip, due to where and how the BPs were issued. It could've been the government's own checks (but in that case, I'd expect to have been picked up at BOS), DL's own internal checks, or a DL employee anywhere along the route.