Sounds most intriguing. 
100% sure most people will be wanting to understand more (based on your comments) the device must be decoding the FEL layer and displaying it (note: generally would not expect much colour in the FEL layer) - and that does sound like big news!
I think some more details will help here, and a quick and concise way would be some photos - can just be from a phone as long as clear and taken square on and capture the whole screen etc. (i.e. not some weird angle hard to make out blurred photos 
) can just paste into a reply post.
I would suggest the following as a starting point so all can get on the same page:
- Make sure all the settings are set as expected - set to use Lossless.
- Reboot the device.
- Take a photo of: Settings → CoreELEC → About
- Take a photo of: Settings → System → CoreELEC
- Make sure to scroll and capture all settings here - probably two photos.
- Play the BL_EL.mkv
- Take a few photos showing the two layers - most obvious is the woman and camera.
- Take a photo of the on screen overlay showing the EOTF etc. (Keyboard “O”)
Files for you and others to test, original BL_EL and BL and EL on their own so can see what each is adding: