When trying to remove a mind fragger, sometimes you hit the head of the victim, even though the Mind Fragger is 100% within the reticle while using a single shot weapon. This is probably because the head hitbox clips through the mind fragger.
If shooting it off there’s always a chance the round will penetrate and hit the head. That’s why the game tips recommend using a pistol, so you don’t accidentally kill the fragger and your soldier with the same shot. Best method is bashing from one of the corner spaces. Bashing from the front center space can cause the hand/weapon to clip through the fragger and smack the guy underneath in the face.
If it would “penetrate” it would penetrate and therefore damage the fragger. It does not. This also happens with pistols, by the way. Bash is the best, of course … but shooting through the fragger without damaging him at all while damaging the head beneath it clearly is a bug, hence this Bug Report.
That is certainly a different situation then. The title of the thread must not have registered in my head when I originally read the post.
More than likely the target moved after you told your guy to take a shot. They never hold completely still, even when you go to zoom in you can see the targets moving very slowly. So even lining up a perfect shot with the full outer reticle focused on the head won’t stop the guy from moving his head before your troop actually fires the weapon.
It did not. This really does happen, people … Is this so hard to believe ? 
nah, it is just head hitbox being bigger than fragger hitbox, often can happen when you shoot at the back of the head as fragger is mostly at the guy’s face.
Please reread the OP. Especially the part where it says
Meaning I did not shoot the back of the head.
I’d really appreciate if people would stop trolling this bug report.