Its been reported and under investigation by the developers. As far as im aware so far, it came down to an Arcade modifier that was applied to the weapon treating it like a pure A2A unlike the other ATGMs. Against air targets it hardly ever worked beyond 8.6km, It was only really evident on stationary or slow ground targets as the missile had more inertia even when the motor technically "stopped".
As I understand it will be corrected with the modifier removed.