Host Name Resolution from Parent Domain to Member Server on Child Domain

We have a parent domain, abc.local.  
We recently created a child domain dev.abc.local.  
The member machines in questions are VMWare guests machines.  
The VMWare host continues live on abc.local.
We want the domainadmin.abc.local to rdp to membermachine.dev.abc.local using only the host name.  
This appears to work when attempting to connect to somemachine.dev.abc.local but not othermachine.dev.abc.local.  
All machines were configured the same.
The internet protocol version 4 (TCP/IPv4) is used in every case.
TCP/IPv4 properties are set to use static IP address, subnet mask, and default gateways.  In addition, a preferred DNS server and an alternate DNS server are specified.
Advanced settings show the assigned static ip address and default gateway under the IP settings tab.  
Under the DNS tab, the primary dns server address (the dns address for dev.abc.local) is listed first and the alternate dns server address (the dns address for abc.local) is listed second.
Under the section for the resolution of unqualified names the defaults are selected which are 1) Append primary and connection specific DNS suffixes and 2) Append parent suffixes for the primary DNS suffix.
Finally, the check box is selected for the option to Register this connection's addresses in DNS.

Why are we able to rdp from the parent domain (abc.local) to a machine on the child domain (dev.abc.local) using the unqualified hostname and others require the FQDN?