Auto Exposure, when enabled, will affect the Distance Field Ambient Occlusion visualization mode in an unwanted way. The visualizer shows a grayscale image with a white background and the parts darkened showing the shading applied to the scene by DFAO. However, as Auto Exposure lightens the scene, the visualization also becomes lightened, causing it to “blow out” as details are pushed into the ceiling and become white. In a dark enough scene, the visualizer just becomes completely white, rendering it useless, even though DFAO shadowing is fully present.
It also seems to “lock” the current exposure when you enable the visualization. Ideally this would bypass the adjusted exposure level altogether.