Connect to DNS automatically, blocks access by NATed bind resolver

I went through some days troubleshooting this issue with the help of my LUG
and now have understood why I could not access my ISP's website while using
my own DNS resolver on my LAN.

One can read the thread conclusion here if you want more indications of the tracing:

http://nslug.ns.ca/pipermail/nslug/2015-August/026794.html

I run a bind resolver on Linux behind the asus merlin firmware router.
I'm on 378.55 and the model is RT-N66U

If I have checked Yes to:

Connect to DNS...

Connect to DNS automatically, blocks access by NATed bind resolver