Little issues with cron and watchdog

In LuCI->System-> Scheduled Tasks is shown */5 * * * * /sbin/ seems its default fan control script from OpenWRT?
And this Scheduled tasks didnt work because the file /etc/crontabs/root (this file edits LuCI) has wrong permissions.
After fixing permissions and restarting cron in this file appears

DO NOT EDIT THIS FILE - edit the master and reinstall.
(/etc/crontabs/root installed on Tue Oct 11 17:28:41 2016)
(Cron version V5.0 – $Id: crontab.c,v 1.12 2004/01/23 18:56:42 vixie Exp $)

But dont know which file is master? Cron use files int /etc/crontabs/ and /etc/cron.d/

Another issue when using different resolver then kresd or unbound watchdog tries restarting service resolver every 5 min.

For info my temp when idle 68C

We got the same when we used the scheduler in the LUCI interface.

Anyone have an idea on what the advised method is to use Cron on the Omnia?