I've just installed 7.90.003 on my RPi 3.
The only addon I have installed is Emby for Kodi (beta version 2.2.14 - however i have also tried with the current stable version of 2.2.10 and get the same behaviour.
While Emby is attempting to populate my library, the system freezes and eventually reboots itself. It doesn't appear to be based on any specific media and it hangs on a different file every time.
debug log (hopefully i've done this correctly this time) - i've used kodi.old.log because of the crash: fFUH
I'm not sure if this is a LibreELEC issue or an Emby issue. I'm going to post on the Emby forums as well.
Edit: I also should note, that I had the same setup under 7.90.002 and didn't come across this issue.
Edit 2: I have also just noticed that it seems I'm getting the Raspberry Pi power warning in the top right of my screen. It is not consistent, but is flickering on and off close to when the crash occurs. I am using a proper power supply purchased in a Canakit.
Cheers,
~Raze