RMAN retaining too many archivelog backups

We have the number of backups for RMAN to keep set to 2 with "CONFIGURE RETENTION POLICY TO REDUNDANCY 2;".  We do weekly full backups of the database and several archivelog backups every day.  The script that does the database backup also does a "delete noprompt obsolete".  Our latest weekly backup just completed, and RMAN purged the database backup files from the backup 3 weeks ago, as expected.  However, RMAN insists that it still needs archivelog backups for the past 2 months.

This does not make any sense to me, as any archive log prior to the full backup from 2 weeks ago should be useless.  is RMAN confused, or am I, and there should be some other command that should be used to get RMAN to remove the unnecessary archivelog backups?