Look at the attached screenshot. The character is indoors, and behind him is a stone wall. However, the reflection of the weapon's scope shows an open field, forest, and sky.
The way to fix this, would be to possible apply RTT reflections for scopes, similar to rear-view mirrors and CROWS screens. Or, for some firearms scopes, just remove reflections altogether. Many firearm optics are designed to minimize glare, such as the EOTech holographics.