Archive log not auto deleted by Oracle even already backed up

Hi,

I have a 18.8.0.0.0 database in Oracle linux 6 with rman archivelog deletion policy and retention policy configured as below,

CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default

CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO 'TAPE';

When I run rman backup, the output show below output

skipping archived logs of thread 1 from sequence 668 to 1334; already backed up
skipping archived logs of thread 2 from sequence 461 to 998; already backed up

When I query the v$flash_recovery_area_usage, the archivelog used 100+ % of the recovery area

I am confused why the archivelog won't be auto deteled by Oracle even though they had already backed up.