I did the steps above, but the issue persists. I didn’t have SSH enabled so I couldn’t log it, but I will try to get a log next time.
I’m not sure what causes it exactly, but it keeps happening. I can still use the Kodi web interface to reboot, and everything goes back to normal.
Log is also available at smb://libreelec.local/userdata/addon_data/service.emby/logs/embyserver.txt