I just noticed this after equipping a scope a few days ago. Whenever I click on a mod in a weapon slot or an empty mod slot the game pauses for half a second or so and then just continues to display the weapon page. However, if I hit ESC it refreshes the weapon screen as if it had been displaying the mods and I just backed out of that screen, if that makes sense. Anybody else seeing this? Even better, anybody have a solution?