I was recently “upgraded” on a b2b and both UG to different cabins, of course.
No UG was on my bookings, my TA was NOT notified. I just happened to check over my bookings and noticed it.
The cabin was then open for sale, of course over the weekend. So, on Monday my TA was able to get my original back on both sailings. It was not operational, if they were going to re sell them.
The upgrade they gave me was on a deck with a smaller balcony, one fwd and one aft. Definitely not an UG IMO.
So, check your cabins periodically. It’s still happening, even with bidding going on.