550BN Deep color issues with Sony UBP-x700M/LGOLED65GXPUA


I’ve noticed a weird quirk with my new sony 4k blu-ray player. Both it and my LG oled tv can output deep color at 10-bit. The 550BN is supposed to be able to handle at least that much.
I can get as far as the menu screen on blu-ray player but as soon as I start a movie the whole screen goes black. As far as I can tell its not a matter of auto-switching of inputs. It’s still the same input as before. If I disable deep color on my tv I can see movie playback with HDR (I’m assuming at a lesser bit depth).

My next step in troubleshooting is to get a pair of high-bandwidth cables since I’m not entirely sure that the cables I’m using aren’t the cause.

Beyond a cable-swap, is there anything else I can try to get this to work?