Early afternoon on Sundays, both today and a few weeks ago (12:15pm today and about 2pm earlier).
The D concourse security lane was totally closed today.
What's irksome is that there are 2 lanes at the C concourse, but the old Preferred lane is closed, leaving one lane that's "Preferred" in name only (but for everyone). All that needs to be done to restore the old Preferred lane is to just remove the rope that shuts off the lane. There has always been just 1 TSA ID-checker there, so that doesn't need to change.