Replicated a few times in GM.
Appears to be when ADS, on being suppressed or hit on weapon/limb will force exit ADP (maybe?) Then the binocular overlay appears on top of the current view. (binoculars are not in inventory or equipped). Occurred with scoped and non scoped weapons.
Repeatedly re-appears after on reloading weapon and firing again.
Going to third person removes the effect. Going back to ADS removes, but exiting ADS to first person sometimes the binocular mask returns.