They were hitting a jeep with a ATGM they must have plenty to go around!
Sometimes once the full range of the missile is reached it detonates I don't know how far that missile traveled but it could be that it just detonated once it ran out of fuel
RPG rounds do the same once they reach like 800-900 metres they just explode and it's been known that the detonation has knocked out the target if the operator of the RPG is well skilled and knows the distance accurately
Jihadists arent that bright, they will waste them by the dozens