As an A-List'er I have had 2 flights this past week where I was not automatically checked in. I had an existing reservation and had to change to an earlier flight. I did this about 32 hours before the flight. Because I did not receive auto check-in I manually checked-in around the 23 hour mark and received mid-B group boarding, Thinking it was an error I reached out and heard that because my (changed) booking was made less that 36 hours before the system does not automatically check you in. My question is...why? If you are not on A-List you can't check in until 24 hour before so why the 36 hour rule?