DNS issue

This probably isn't an AREDN software issue, but I need some assistance.

I'm struggling to find the root cause of long DNS lookup times on several Raspberry Pis on our network.  Each uses a local node as its DNS server.
The DNS actually works, but is very delayed.    I've disabled IPv6 on the RPIs, which didn't help.   Here's the resulting /etc/resolv.conf on one the RPIs:

# Generated by resolvconf
domain local.mesh
nameserver 10.101.58.249

But when I do a host command, it takes 20 seconds to finish:

pi@gnb-rpi:~ $ time host w6bi-shack-pc
w6bi-shack-pc.local.mesh has address 10.95.109.98
;; connection timed out; no servers could be reached
;; connection timed out; no servers could be reached

real    0m20.208s
user    0m0.090s
sys     0m0.000s

What DNS service could the RPI be waiting for?

Thanks.

Orv W6BI