I have a Streambar Pro, Sony 4k TV, and 4k DVD player. First, note that other than the Ultra HD disc, all other content (dvd / streamed programs / TV programs) plays perfectly.
I have checked that all devices are updated. The disc I mention will play if I use the TV speakers. The previews etc on this disc also play fine - it goes silent when the movie begins. The HDMI cables are high-quality (both the DVD-to-TV, and TV-to-Roku).
I contacted Sony support, and they state their products' settings are correct.