With NQNMODE=NQNAME specified in the VTAM start options my sessions are now failing with 087D0001.

This is how NQNMODE works. When you take the default NQNMODE=NAME or code NQNMODE=NAME VTAM will add the resource by the fully qualified network name (REAL) in storage under that NETID. VTAM will also create add the (ALIAS) name without NETID and point it to the (REAL) definition. With NQNMODE=NQNAME VTAM only adds the resource under the NETID specific table (REAL) and not point an (ALIAS) definition to the REAL definition. In order to start a session with NQNMODE=NQNAME the fully qualified name needs to be used. The ALIAS name will fail. In order to display it the fully qualified name needs to be used. Typically you would want your VTAM start option to be NQNMODE=NAME and override it with a CDRSC definition by coding NQNMODE=NQNAME for a specific resource. If you want to use NQNMODE=NQNAME in your start option then you will need to use fully qualified names for all session request and displays unless you override it with a CDRSC specifying NQNMODE=NAME.

http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/f1a1b6c0/4.3.120