I'm not sure if this is normal (I think not) but here's a Tacview of me trying to shoot a Sidewinder in the sky (15° above horizon, no lock tone) while a friendly harrier is below me, coming at me at my left side.
When the missile launches, it steers a hard 90° left turn, immediately follows with a right S and kills my unsuspecting wingie.
I didn't know our Sidewinders could do this ; can they ? Or do they need a bit of nerfing ? who-needs-aim9x-when-they-have-a-harrier.zip.acmi.zip