MacOS – How to fix when I can nslookup and dig an internal hostname, but I cannot ping or ssh to the internal machine

I can nslookup and dig an internal hostname, and I get a rapid response, but I cannot ping or ssh to the server. All external hostnames work fine for both ping, ssh, dig or nslookup.

ssh -vvv xxxx-xxx-xxxx-1.xxx.xxxx.net
OpenSSH_5.6p1, OpenSSL 0.9.8r 8 Feb 2011
debug1: Reading configuration data /Users/gregcain/.ssh/config
debug1: Applying options for *
debug1: Reading configuration data /etc/ssh_config
debug1: Applying options for *
debug1: auto-mux: Trying existing master
debug1: Control socket "/Users/gregcain/.ssh/master-gregc@xxxx-xxx-xxxx-1.xxx.xxxx.net:22" does not exist
debug2: ssh_connect: needpriv 0
ssh: Could not resolve hostname xxxx-xxx-xxxx-1.xxx.xxxx.net: nodename nor servname provided, or not known

I've done a lot of searching on the net, and on this site, and it appears it's got something to do with mDNSresponder. I've added two stanzas to /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

-AlwaysAppendSearchDomains <- this shouldn't matter, since I am using FQDN. 
-NoMulticastAdvertisements <- I believe this one disable bonjour broadcast

I've also tried turning off mDNSResponder, but then name resolution fails outright. If I add entries to /etc/hosts, then I get working name resolution. But I need to be able to connect to DNS.

I'm pretty confident our DNS is setup correctly, as it works for everyone around me. I've also spun up a linux VM, and I'm able to connect as I would expect, using the same /etc/hosts and /etc/resolv.conf.

Any suggestions would be greatly appreciated.

UPDATE – >
nslookup

set all
Default server: 10.xxx.xxx.xx1
Address: 10.xxx.xxx.xx1#53
Default server: 10.xxx.xxx.xx2
Address: 10.xxx.xxx.xx2#53

Set options:
  novc          nodebug     nod2
  search                recurse
  timeout = 0       retry = 3   port = 53
  querytype = A         class = IN
  srchlist = corp.amdocs.com