The initialization of the CEC adapter has a bug. On your working LE 12.0.1:
2024-02-27 18:26:18.011 T:916 debug <general>: InitialiseFeature - using libCEC v4.0.7
2024-02-27 18:26:18.012 T:899 info <general>: starting zeroconf publishing
2024-02-27 18:26:18.012 T:911 error <general>: CCurlFile::CReadState::FillBuffer - (0x7fff1401ca40) Failed: Couldn't resolve host name(6)
2024-02-27 18:26:18.012 T:927 debug <general>: Thread EventServer start, auto delete: false
2024-02-27 18:26:18.012 T:925 debug <general>: Thread CECAdapter start, auto delete: false
2024-02-27 18:26:18.012 T:925 debug <general>: OpenConnection - opening a connection to the CEC adapter: /dev/cec0
2024-02-27 18:26:18.012 T:912 error <general>: CCurlFile::CReadState::FillBuffer - (0x7fff080532d0) Failed: Couldn't resolve host name(6)
2024-02-27 18:26:18.012 T:912 error <general>: CCurlFile::Open - <https://mirrors.kodi.tv/addons/omega/addons.xml.gz?sha256> Failed with code 0:
2024-02-27 18:26:18.012 T:916 debug <general>: Initialise - initialised peripheral on '/dev/cec0' with 2 features and 0 sub devices
2024-02-27 18:26:18.012 T:916 info <general>: Register - new cec device registered on cec->/dev/cec0: CEC Adapter (0000:0000)
2024-02-27 18:26:18.012 T:916 debug <general>: GetMappingForDevice - device (0000:0000) mapped to CEC Adapter (type = cec)
2024-02-27 18:26:18.012 T:912 error <general>: CRepository: failed read 'https://mirrors.kodi.tv/addons/omega/addons.xml.gz?sha256'
2024-02-27 18:26:18.012 T:910 debug <general>: CAddonDatabase::GetAddons took 48 ms
2024-02-27 18:26:18.012 T:911 error <general>: CCurlFile::Open - <https://addons.libreelec.tv/12.0.0/ARMv8/aarch64/addons.xml.gz.sha256> Failed with code 0:
2024-02-27 18:26:18.012 T:911 error <general>: CRepository: failed read 'https://addons.libreelec.tv/12.0.0/ARMv8/aarch64/addons.xml.gz.sha256'
2024-02-27 18:26:18.012 T:916 debug <general>: InitialiseFeature - using libCEC v4.0.7
2024-02-27 18:26:18.013 T:930 debug <general>: Thread CECAdapter start, auto delete: false
2024-02-27 18:26:18.013 T:930 debug <general>: OpenConnection - opening a connection to the CEC adapter: /dev/cec1
2024-02-27 18:26:18.013 T:916 debug <general>: Initialise - initialised peripheral on '/dev/cec1' with 2 features and 0 sub devices
2024-02-27 18:26:18.013 T:916 info <general>: Register - new cec device registered on cec->/dev/cec1: CEC Adapter (0000:0000)
2024-02-27 18:26:18.013 T:916 debug <general>: Thread PeripBusCEC 140733637783296 terminating
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On your non-working LE 13 nightly (20241103-f662bea):
2024-11-05 16:49:04.830 T:1046 debug <general>: InitialiseFeature - using libCEC v4.0.7
2024-11-05 16:49:04.830 T:1057 debug <general>: Thread CECAdapter start, auto delete: false
2024-11-05 16:49:04.830 T:1057 debug <general>: OpenConnection - opening a connection to the CEC adapter: Linux
2024-11-05 16:49:04.832 T:1046 debug <general>: Initialise - initialised peripheral on 'Linux' with 2 features and 0 sub devices
2024-11-05 16:49:04.832 T:1046 info <general>: Register - new cec device registered on cec->Linux: CEC Adapter (0000:0000)
2024-11-05 16:49:04.832 T:1046 debug <general>: Thread PeripBusCEC 140732832476800 terminating
In the working log, the CEC adapter is registered at /dev/cec1, in the non-working log at Linux.
I've already reported the bug to the devs. Stay tuned.