This is not random, when you right click you do not only zoom in but you also hold your breath in order to minimize movements of your sight.

When scoped you can use "+" and "-" to zoom in and out without holding your breath.

Although like most things ;) It is bugged in a specific circumstance, when you are not aiming with a weapon, zooming in and out always hold breath.

Phas3r, I believe this is related to just holding right mouse button while moving to look around etc. not specifically to holding breath while aiming down sight/optics.

Why lose breath if there is no hold breath ;)