Received the new HDMI cables last night. Hooked them up, and got no flickering when using 1.4 Changed the settings, as suggested, re-enabled HDCP 2.2, and went directly from the Pro to the receiver. It flickered for about 20 seconds, and then stopped. It's been solid since. So weird. Something is amiss still for sure, but I'm happy I can play Horizon with HDR on. It looks so sweet.