Yes, I was referring to a discounted rate called "Marriott Rewards Rate," not a free night with points.

Thanks for the replies everyone. This is what I thought based on past experience, and I will submit a missing stay request.

Oddly, though, I did receive some points for that stay, but they appear to be (based on my calculations) for restaurant and bar charges only, not the room charge. In my account it shows check-in/check-out as the same date, and I also did not earn any qualifying nights.

In addition to the discounted rate, I also used $100 Bonus Bucks, if that makes a difference.