The next week after the portal had opened, I get a call from the Westin telling me that the rooms were listed as available by mistake and they were cancelling my reservation.
From what I've read from you, you made your reservations in January, right?
Unfortunately, you are not the only one that this happened too. I've found that booking with points and my rewards membership is a pretty safe thing to do. Though, of course, I always have an option A and B. That said, I do have gold status with Bonvoy which is a slightly higher tier so that might be part of it.
I have terrible luck with the housing lottery so I usually buy downtown hotel rooms out of block and I have about a fifty fifty chance of getting my hotel reservation cancelled. I’ve booked seven hotel rooms in the past four years and had three cancel on me. I’m kind of numb to it now honestly. This year was bad because usually my rooms get cancelled because they forget when gencon is and put out cheap hotel prices and then cancel them; this year I paid 450 a night for the Marriott and they cancelled me still.
On the the plus side I’ve never been cancelled after about February so I’ve had time to get a different room. Also one year I got the Conrad and only paid about 195 a night which is cheaper than the housing portal and they honored it.