I am running video add-on.
Oddly, it didn't happen again, even I have waited about an hour.
So I didn't manage to capture anything useful on the log file.
Will try again tomorrow.
I didn't connect a keyboard to Pi.
I am navigating Kodi with my TV remote via HDMI CEC
Wish to add that I initially setup the system on RPi2.
After which, I copied the image and ran it on RPi3.
Not sure if this is the cause of the problem.