As long as the backups are retained by SMO, it will also have the catalogued information in RMAN.
Even if the backup is freed(snapshots are deleted and SMO maintains information in repository), then still the information will be available in the RMAN catalog.
If you are not using "Protection Manager", please check /opt/NetApp/smo/properties/smo.config. The parameter retain.alwaysFreeExpiredBackups should be set to false.
If this is set to true, SMO will retain all the backup information in SMO repository as well as in RMAN catalog. This will increase the size of the repository database and RMAN catalog or control file.
SMO will uncatalog the information from RMAN only when the backup is deleted via SMO.