Okay to be honest I am not sure if I am just not communicating myself clearly or you are trolling me here. As I generally do not like to assume the worst in people, I decided to have one final go at this. Below I have posted a video that shows the issue in question in much greater detail, and contrasts that with the normal in game cover mechanic.
A few things to bear in mind with this are:
1) In both cases I am using the exact same control scheme.
2) I am using nearly the exact same sequence of keystrokes. (The only reason they do not look the same is because anytime I attempted to move while against a wall the game took me out of cover.)
3) It is in exactly the same place on the same map.
4) The only differences are that these two games took place about 2 days apart, and that I reset my key bindings before recording the second sequence.
So given that the game quite clearly allows me to hip fire while using that specific pillar as cover without the gun model clipping into it: there are two possible conclusions that we can draw here.
1) A bug exists with using the hold option to enter cover that periodically causes you to leave cover anytime you attempt to move or hip fire around corners.
2) The cover system is so poorly designed that the game prevents you from being able to repeatedly perform the same actions from one game to the next.
Now given that I have played several hundred round in game I am fairly positive that the latter is not the case. Regardless, if either is true it is a bug with the cover system that needs to be fixed.
I created this post in the hope that it would bring said bug to the attention of Ubisoft's GRO development team so that they could perhaps fix it in a future patch.
If you still do not agree with me on this point: then I guess we will just have to respectfully agree to disagree.