Windows server 2012 R2 Conditional Forwarder: NSlookup fails the first time

Hi,

Windows server 2012 R2.

I have a conditional forwarder added to resolve to the customer domain (abc.com).  When I do nslooup -type=mx abc.com it fails the  time and it resolves the second time.

My domain contoso.com (not my real domain)

First nslookup

c:\> nslookup -type=mx abc.com
Server: DC1.constoso.com
Address: 192.168.1.5

DNS request timed out was 2 seconds.
***Request to DC1.contoso.com timed-out

Subsequent nslookup

c:\> nslookup -type=mx abc.com
Server: DC1.constoso.com
Address: 192.168.1.5

Non-authoritative answer:
abc.com       MX preference =1, mail exchanger =mail.abc.com

mail.abc.com internet address = 10.10.0.5

Any ideas what might be  this issue?

Thanks,