Libreelec Changes Video Calibration On Start

Set the TV to "just scan" or similar instead of calibrating the screen.

Connect the RPi directly to the TV and see if the video issues are gone. If they do, the inline AVR is the problem.

Get us a full Kodi debug log via pastebin, or other download website.

Our crystal ball is not capable enough to read full log files.

Beside the fact, that we willl ofc need the full debuglog, can you please tell us EXACTLY how your devices are connected? Where does the RPi gets its power from? From the TV USB or a real power supply? Are your devices connected like this:

RPi -> HDMI -> AVR -> HDMI -> TV?

As we also just don't know which kind of video you are trying to play and it might be the case that it's MPEG2 or VC1 (sometimes FullHD movies have VC1) it could be, that you will need the licenses:

config.txt [LibreELEC]

But as Klojum already said...we will need the full logfile.

Debug log .. or your problem is not our problem

Please don't let us download files from your dropbox. There are many paste-services on the net which you can use.

If you don't know how to submit logfiles, please read this: Provide Log File [LibreELEC.wiki]

yw