There is currently a max airspeed of the target for the sensor to keep tracking it. The missile should be able to track targets travelling up the 450 km/h (240-ish knots) currently, assuming it stays in the seeker FOV and slew rate. At least we have the missile able to track airborne targets.
No problem tracking helicopters and slow flying aircraft. Might tweak the value a bit.
However, it is not a air-to-air missile, even if it is tremedously fun to use it that way.