I used to have this problem too but I think it went away when my original Bolt failed (Pink Screen/No Video) and TiVo sent me a replacement Bolt, I really can't remember when/why it stopped but I'm leaning toward the replacement Bolt. As long as your HDMI cables are "High Speed" your cables will work fine. If your switching through an AV receiver, you could check updating the firmware on that receiver. I also found out my receiver was not HDCP 2.2 compliant. The sticker on it stated 4k pass through but I was not getting 4K 60fps. I know how frustrating it was for me so here is what I would recommend "at this point"... Go buy a new TiVo Bolt from Best Buy or TiVo and install it, then return it after testing. You will be able to tell if it is the Bolt or something else in your current setup. This will be the fastest and simplest process of elimination to determine if its the Bolt. Sounds like you have spent enough time troubleshooting and trying other fixes, now you must try a new Bolt.