This is the pushback method I was using.
The first part of this video shows the results I was getting, Location is LIME.
The second part shows the AI behaviour after a runway/wind direction change, which was the expected result.
I've noticed this behaviour at or locations so it seems to be a bug in the AI pushback system rather than a groundnet error.
My conclusion from this is AI pilots would make rubbish NASCAR drivers if they can't do a simple left turn