Starting from LibreELEC-RPi4.aarch64-13.0-nightly-20240904-fd1b4e2 my CEC stopped working.
I confirmed that it works for LibreELEC-RPi4.aarch64-13.0-nightly-20240829-b200261, but not for LibreELEC-RPi4.aarch64-13.0-nightly-20240904-fd1b4e2, the following nightly in https://test.libreelec.tv/13.0/RPi/RPi4.
Digging a bit in the GitHub repository, I found only one CEC-related commit introduced between 20240829 and 20240904, which seems to remove the feature introduced by this one. Could this missing feature be the culprit of the issue?