As a matter of fact, I just experienced this yesterday (upgraded on the app, then a room only was assigned to my booking, when I checked-in in the lounge), but I was able to get that fixed.

This being said, if I was a manager, I would have given some kind of compensation to the guest that was upgraded to a larger suite (even if it was only the app) to keep him somehow happy and to try to get the guest back for future stays in the city and to avoid eventual negative social media posts and a possible poor survey.
It's just good business practice in this industry.