What happened:
Flying in multiplayer server against AI F5 with Aim9P5 missiles. Took them straight into the Vertical flying directly into the Sun so they wouldn't be able to get a lock with their IR missles. They were directly in my 6 so not only should they have been visually blind (Another issue...), their missile seekers should have been saturated.
They were able to launch a tracking IR missle against me which I wasn't able to defeat with flares either. Completely ruined immersion.
I suspect its a whole AI / Missle issue rather than just an issue with the P5?
Fix: AI unable to launch IR missles into the sun,
(Bonus fix: Lose SA on your AC when flying into the Sun/Cloud/Behind terrrain..)