With the aim misalignment bug (the one where your gun is not aligned with the crosshair) , you can cause it by using aim, while in prone, (point-aim), and moving around your aim on a downward slope, on terrain, not uphill, or flat.

You can also cause it by using ALT-LOOK, to point your gun high, or low, demonstrated in the footage, with the SVD. So ALT-Looking, can really make this bug bad, especially, you point your gun straight up into the air, and shoot people without the gun even near pointing at them.

*Main Cause* Using Point-Aim, while prone on a downward slope (uphill, and flat should be fine, few exceptions however)
*Main Cause #2* Using ALT/Free-Look to point gun straight up/down, and going prone, and starting to aim around in point aim, on any slope (flat, upward, downward)