Installed LibreElec stable on a NUC5PPYH with pulse8 CEC adapter. Adapter is recognised in libreelec, TV recognises CEC as "CEC adapter", connects but the remote control buttons don't actually do anything, the TV "disconnects CEC" after about 2 minutes.
Installed Windows 10, installed KODI 16.1 Jarvis, installed libcec3.0 windows. CEC adapter is recognised by the TV as "Kodi" and the buttons work - TV did not disconnect CEC overnight.
Installed openelec older version 5 (kodi 14) on rasp PI2, using inbuilt PI CEC tv detects CEC as "Kodi" and buttons work. I used this setup for 12 months+ without CEC issues.
Any ideas on why the standalone LibreElec wont work? I even tried the "new" alpha krypton (don't like the new interface skin but hey ho personal preference and all) but that didn't change anything. I don't know if I should try an older version of libcec (I didn't see which version was used in the old pi2 openelec - i'll boot that up again tonight and check versions), how can you "downgrade" libcec? I don't mind fiddling via putty....
At the moment I have left the system dual booting W10 and LibreElec stable (with the BCD default to W10 - autologin with KODI opening, this adds a lot of overhead to boot time though!)