named[24408]: network unreachable

[Chris]

I know this is a very, very simple question with probably a very simple
fix but I've been messing with this 14.04.4LTS -> 16.04.1LTS upgrade
since last Tuesday and I'm fried. I have bind9 running as a local
caching nameserver especially useful for my spamassassin queries. I
keep getting a whole lot of what's in the subject line in my syslog
which makes it grow very large. Again, this is an issue I didn't have
in 14.04LTS. For instance this line:

named[24408]: network unreachable resolving 'succulentsandsunshine.com

If I run:

chris at localhost:~$ time host succulentsandsunshine.com
succulentsandsunshine.com has address 45.79.72.219
succulentsandsunshine.com mail is handled by 20 mx2.emailsrvr.com.
succulentsandsunshine.com mail is handled by 10 mx1.emailsrvr.com.

real	0m0.366s
user	0m0.036s
sys	0m0.004s
chris at localhost:~$ time host succulentsandsunshine.com
succulentsandsunshine.com has address 45.79.72.219
succulentsandsunshine.com mail is handled by 20 mx2.emailsrvr.com.
succulentsandsunshine.com mail is handled by 10 mx1.emailsrvr.com.

real	0m0.040s
user	0m0.036s
sys	0m0.000s

I don't see a network unreachable error. My /etc/resolv.conf file is:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by
resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1


nameserver 127.0.0.1
search PK5001Z

and it's linked to ../run/resolvconf/resolv.conf which is the same as
/etc/resolv.conf (which it should be)

/run/resolv.conf/NetworkManager however reads:

search PK5001Z
nameserver 127.0.1.1

/etc/network/interfaces reads:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
	dns-nameservers 127.0.0.1

So, question is, why do I keep seeing lines like this in my syslog:

Aug  8 15:23:31 localhost named[24408]: network unreachable resolving
'c.go-mpulse.net.cdn.cloudflare.net/A/IN':
2400:cb00:2049:1::c629:df1f#53

Aug  8 15:23:35 localhost named[24408]: network unreachable resolving
'pop.embarqmail.com/A/IN': 2001:428::5#53
-- 
Chris
KeyID 0xE372A7DA98E6705C
31.11972; -97.90167 (Elev. 1092 ft)
15:12:48 up 1 day, 18:37, 3 users, load average: 0.44, 0.42, 0.44
Ubuntu 16.04.1 LTS, kernel 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016