I had this happen to me twice this summer at two different properties. I had booked a stay at the JW Marriott in Cancun. After booking, my MIL decided to come with us for part of the trip.

I booked the second room under my name as a separate reservation. I paid for both rooms.

Initially, I only received nights and points credit for the shorter stay for my MIL. I contacted Bonvoy, and also contacted the property. The property provided all of the invoices which showed both rooms in my name, etc.

After a couple of weeks of back and forth via email I was eventually given nights and points credits for the longer reservation without a response or explanation from Bonvoy customer support.

The property said that I should be credited with points for both rooms. Bonvoy customer support eventually stopped responding via email. I tried to get a response or explanation for several weeks before I just gave up. The hassle just wasn't worth the few thousand points.

Same thing happened a month later with the same scenario. Only this time it was with the Marriott in Cancun. I received nights and points credit for the longer stay, but not for the second room that overlapped on a second reservation. Contacted Bonvoy customer support again and never got a response.