I've completed this event with my Phoenix team on auto 3 times now, including yesterday. Today Sid is just destroying me. Might be super terrible rng... but 3 auto successes in the first try previou...
If you are right in the edge gear/mod wise then this is likely to happen.
This mission is very difficult and phoenix auto is just the AI we all know and love. A crit not landing or an off chance ability selection can lead to many different scenarios at the start of that round.