DNS BUG delay resolution of LAN DNS

I have a little LAN (3 computers) where each computer uses UBUNTU 14.04 LTS. The LAN has a server that assigns the IP address by MAC ADDRESS and provides DNS resolution for local computers.
The BUG is for each computer of the network (I have not tested the server that is and ODROID and has not monitor and keyboard).
For example a computer is called "core". If I try to connect to "core I got the following message:

ssh -X core
ssh: Could not resolve hostname core: Name or service not known

and if I try lookup command I got

User:marco Computer:i7 Base:marco Current:/media/data/users/home/marco
Command 1003 of 14 $nslookup gaia
Server: 127.0.1.1
Address: 127.0.1.1#53

** server can't find core: NXDOMAIN

After a random time (it can be few seconds or some minutes) the address is resolved

$nslookup gaia
Server: 127.0.1.1
Address: 127.0.1.1#53

Name: gaia.lab
Address: 10.10.100.11

and after the first resolution the address are resolved for all the computers of the LAN. I have not problems to resolve the address outside the LAN.

the reverse address is decoded:
nslookup 10.10.100.11
Server: 127.0.1.1
Address: 127.0.1.1#53

11.100.10.10.in-addr.arpa name = gaia.lab.

The DNS servers are:
nameserver 10.10.100.7
nameserver 8.8.8.8
nameserver 8.8.4.4
/etc/resolvconf/resolv.conf.d/base (END)

where 10.10.100.7 is the server of the network.

Please contact me if I can provide you more information.

Best
Marco Righi

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: resolvconf 1.69ubuntu1.1
ProcVersionSignature: Ubuntu 3.19.0-33.38~14.04.1-generic 3.19.8-ckt7
Uname: Linux 3.19.0-33-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.18
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Nov 15 01:47:48 2015
InstallationDate: Installed on 2015-10-29 (16 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
PackageArchitecture: all
SourcePackage: resolvconf
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.resolvconf.resolv.conf.d.base:
 nameserver 10.10.100.7
 nameserver 8.8.8.8
 nameserver 8.8.4.4
mtime.conffile..etc.resolvconf.resolv.conf.d.base: 2015-11-08T22:04:24.170916