I have a simple scene of just a phone model. The display with a mapped image is one piece of geometry and the glass coating is another atop the display. When the phone geometry gets far enough away from the camera the glass shader becomes opaque. There's plenty of samples and a high enough ray depth because it works fine up close. I'm at a complete loss. Please help.
Could it be related to this? https://answers.arnoldrenderer.com/answers/20863/view.html
Turned out to intersecting geometry. It's a stock model I should have checked more carefully. What was throwing me off was why it worked at all. Seems like there's an invisible threshold based on geometry-to-geometry distance and camera distance.