Mediatek x20 board automatically rebooting

I am facing strange issue where X20 board running android reboots automatically after around some half hour.
Its not sleep state, and time isn’t exactly display sleep time. This I confirmed by changing display sleep time.
When checked android log, it didn’t reveal anything. Last few lines of log shows:

05-26 08:20:49.039 741 741 D wpa_supplicant: wlan0: Control interface command ‘SIGNAL_POLL’
05-26 08:20:49.516 284 642 I AudioParamParser: appHandleThreadLoop(), inotify_add_watch failed! sleep 1 sec to wait sdcard ready…
05-26 08:20:49.732 253 253 E hwcomposer: ! (1) Failed to get presentFence !!
05-26 08:20:50.521 284 642 I AudioParamParser: appHandleThreadLoop(), inotify_add_watch failed! sleep 1 sec to wait sdcard ready…
05-26 08:20:50.778 253 253 E hwcomposer: ! (1) Failed to get presentFence !!
05-26 08:20:51.528 284 642 I AudioParamParser: appHandleThreadLoop(), inotify_add_watch failed! sleep 1 sec to wait sdcard ready…
05-26 08:20:51.732 253 253 E hwcomposer: ! (1) Failed to get presentFence !!

But such log is shown normally and periodically.
I don’t see any power connection issue as board was left untouched.

Anyone facing similar issue?

Thanks,
Shailesh