This explains the donut hole around DC. FAA issued a special security NOTAM to slow your ass down around DC until further notice. Effective today. Fast movers look like they can still overfly but above FL180 (18,000'). The beginning of mandatory IFR rules.
It must've gotten confused as this is a correction. Probably lots of complaints about having to deviate in a super busy corridor…mostly from pissed ARTCC controllers and airlines schedules getting all jacked in a domino effect I'd bet.
Basically, if a plane is within 30NM of DC and below 18K, has to slow to 180kts if able.
30-60NM can go 230kts…almost normal below 10K (250kts) but above 10K, really it's no speed limit as long as you don't go super below 18K.