I have 2 4k capable Rokus (3941x and 4800x). Both are connected to LG C1 OLED TVs. Both of them also are running through an AV receiver. One of these is an Onkyo, the other is a Yamaha. If we have a power failure or there is as system update (this happened this week on the 3941x), I am not able to play any content (the menus work fine) until I go into display settings and have the Roku re-detect the displays. Once I have done this, the setting seems to stick until the next restart.
On both systems I have replaced all the HDMI cables with good quality (8k) cables and this has not resolved the issue. 4k-HDR/Dolby playback works fine. I have the 4k advanced settings on the AV receivers dialed in correctly. Both system have 4k Blu-Ray players connected in a similar fashion and I never have issues with these devices. Why are the Rokus so troublesome?
Connecting both Rokus directly to the LG C1s have the same result. After a reboot of the Roku there is no video on content playback. The menus and normal navigation work. I loaded YouTube, and when I selected a video, some ads came up. There was a bug in the upper left corner telling me Ad 1of2. Down in the lower right was the countdown timer (or Skip Ads) but no video playing underneath (there is sound). In order to get content to play I have to go into Display Type and force a re-detect. The AVR does not really seem to be the culprit here. The Models are Yamaha RX-V383 and Onkyo TX-SR393. I have been in the HDMI secret screen and all lines show Yes, and HDCP Status is Authenticated. HDMI fast suspend and Automatic Recovery are both disabled, because I was having issues with those setting on previously.