TV keeps switching to unused HDMI port

  • Hello,

    every few days my TV acts strange and switches to the HMDI 4 port while showing HDMI 4       (raspberry  ) in the OSD info. Yes, there are some blanks before the closing parenthesis. I don't have anything connected to HDMI 4. When I switch back to "HDMI 1 (MHL)" it takes max 10 seconds, and the TV switches back to HDMI 4 again.

    I write in this forum, because I am running LibreELEC on a Raspberry Pi 3B+. That Pi is connected to an AVR and that AVR goes into HDMI 1 (MHL). This thing started a few ago and I think I also updated LibreELEC around that time from version 9.2 to 9.2.3. That is also the only change in my setup.

    Yesterday, I was watching some Netflix on a FireTV stick, when I found something interesting on Youtube on my phone. I shared the video link with the Yatse app, which sends it to the Pi. There a Youtube addon will play that video. The video was already playing when I paused the movie on Netflix and then switched the AVR to the Pi. That's, when the TV started to think, HMDI 4 is the most important thing in the world.

    I search for anything such as CEC and disabled it on every device: TV, FireTV stick, Pi... did not help. The only thing that stopped the crazy acting was cutting the power for all devices (except TV). Can someone help, please?

    TV: Sony KDL-60W855B

    AVR: Marantz NR-1604

    Pi: 3B+ with LibreELEC 9.2.3 + FLIRC USB dongle

    FireTV stick: on AUX-HDMI port @ AVR

    Remote: Oneforall Smart Control 8 (URC 7980)