AA-missiles can miss when they are on a direct collision course with their target

**The bug**
Even if the AA-missiles and the plane they are trying to hit are flying directly towards each other, the missiles will sometimes miss by flying over or below their target. This does not make sense, as the missile has enough time to turn (and does not need to adjust its heading very much in the first place).

**To Reproduce**
1. Launch a sandbox game with cheats enabled.
2. Enable the `NoDamage` console command.
3. Spawn in a Wailer (or a Restorer) and an enemy ASF.
4. Have the two units attack each other.

The bug is most commonly observed with the Wailer, but it also happens with the Restorer. I assume it can also happen with other units.