Little issues with cron and watchdog

Turris Omnia
1

In LuCI->System-> Scheduled Tasks is shown */5 * * * * /sbin/fan_ctrl.sh 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

2

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?