Networker VBA External Proxies

How does the VBA know which external proxy to use to backup VMs?  Running Networker 8.2.0.1 with 1 VBA and 3 External Proxies.  I have a external proxy for DEV cluster with separate datastores and 2 external proxy for PROD with separate datastores.  When backing up a DEV VM the VBA chooses a prod external proxy for backup which doesn't have access to the datastore and job fails with error NFC_DISKLIB_ERROR.  If the proxy cannot access the datastore it would not use Hot-Add and default to NBD but not sure why the DEV proxy is not being utilized.