Let me try to explain:
My RPi3 with LibreELEC is always on and in 7.95.2 it all works, I turn on the TV and in a couple seconds (not immediately) the CEC starts working, I keep pressing some buttons in the remote and than just works, there's nothing to complain here.
After updating to 7.95.3, when I turn the tv on, the CEC does not work, not even after waiting minutes or pressing lots and lots of buttons on the remote, BUT, if I switch the source from the tv from HDMI 2 (where the RPi3 is connected) to another one, lets say HDMI 1, and then get back to HDMI 2, the CEC starts working fine.
The same issue is happening in the 8.0.0.
Let me know which logs are needed to solve this, I'll gladly provide it.