AA lock-on missiles are ineffective

I lock on, the aircraft pops flares, I wait, after all the flares come out I wait another couple seconds until the flares disappear, then the lock on re-appears, I shoot and the missile starts going after the jet or aircraft then suddenly turns into the ground, and the reticule changes to miss. I know you are supposed to wait for after the flares come out, but it just doesn't work. The missile refuses to chase and makes a visible turn into the ground and crashes. Are the flares bugged and last longer than the graphical effect? This is really concerning because it makes it extremely easy to exploit by pilots and avoid missiles completely by exploiting this flawed missile behaviour.

Yes I am seeing this exact same behaviour! It was confusing the hell out of me when using the AA tank. Flares were well gone but the missile would still turn to the ground instead of chasing. I'm definitely thinking the flare effect is last longer than the visual of it.