Yeah, I’m one of the people affected by this and it has happened to me on multiple machines on multiple updates and I have no idea what’s happening. Of course the keys do not actually work like for everyone else, which is even worse from a consumer UX standpoint (if I didn’t knew better I’d just throw away the old key…)
It's on my todo list to backup and wipe that machine at some point. It's a desktop machine, not a laptop, and I don't save the recovery key to my iCloud, so I don't see how this could be a security threat. But something smells fishy.
