AI Red Air Defense Units Only Target Ground Forces

[King39]

I'm sure this has been covered but I just can't find it:

Specifically, all red Air Defense units cannot (do not) target Allied air units under Advanced Actions / Triggered Actions > Perform Task > Attack Group. HOWEVER they can/do target ground units.

Is it me - am I doing something wrong or is this a bug? I just can't believe this hasn't been discussed before now.

Any advice would be appreciated.

Thanks,

John