It is a Sideshot.
A Sideshot in a not very well simulated game engine, sadly.
The side shot arc is far too big and doesent consider the angle of the incoming projectile (afaik).
but when its like this, than this is a bug which should be fixed.
Sideshots are sideshots... never had stuff like this in wargame (with 1000+h in the franchise)
edit: lol, checked it... its actually 1200h, crazy stuff