I also don't believe that's how it works, for SMS at least. Authentication can also fail due to a broken device or to a poor connection. Does that mean SMS mess

I also don't believe that's how it works, for SMS at least. Authentication can also fail due to a broken device or to a poor connection. Does that mean SMS messages can get lost? Doesn't make sense. Also, since this is a race condition, it means that the exploit can't block all incoming calls.