lb1.dub.prod.101domain.com has no CNAME records.
Question and response
Question
dig lb1.dub.prod.101domain.com. NS
Answer
The response has no answer records.
Authority
prod.101domain.com. 10800 SOA NS1.FASTTRACKDNS.com. ADMIN.prod.101domain.com. 2015126978 10800 3600 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0