This issue occurs for all weapon scopes and iron sights however it is only really a major issue for the "fullscreen" weapon sights that overlay a cross-hair and do not render a 3d model of the scope as the cross-hair is locked to the centre of the screen and it is not immediately obvious that the players view is not aligned with the weapon. 3d rendered scopes and iron sights do not suffer from this problem so much as it is more obvious that the players view is not correctly aligned with the weapon sights.