As someone who was affected by this myself, I can say that they ultimately did right by their mistake. They did not rescind the acceptances. They accepted all affected students.
Most of those affected never even knew and it never really mattered that they didn’t know. They never sent out a letter saying “We made a mistake,” or anything of the sort. It upset me so much at the time because I was waiting for my official letter and so I called them and that’s when this bomb was dropped. But the next day, they sent out the official letters. The lesson learned here, for me, was to wait until you get the tangible acceptance offer letter (and even then, schools like UCLA and Mayo have messed up).