[Realized this is largely a duplicate of the same points as [url=https://www.flyertalk.com/forum/members/c17psgr.html]C17PSGR -- apologies]

I do not think anything has changed.

https://www.marriott.com/help/rates-faqs.mi
"To be eligible for government discount rates, guests must be an active duty member of the military or current employee of any level of local, county, state, or federal government within the United States."

Government contractors--which is what it sounds like the OP is--are not eligible for Marriott government rates, at least officially:
https://www.marriott.com/File%20Bloc...eals/chart.htm

This is not new.

I'm a federal employee, and our office does sometimes have contractors work for our office who are only reimbursed per the government per diem rates. We issue them letters, etc., but the hotel is under no obligation to honor per diem or allow them to book the government rates. It's a property decision. Many will work with them because it's good business in many cases to do so. I'd suggest talking to the hotel management about your needs to work out an arrangement.