HBS dedup not reducing size on cloud-side

[tribunal3117]

I'm backing up local weekly VM backup files to the cloud using dedup. It works very well, reducing 100GB of files to process down to 14GB. These local backups are rotated weekly, with 4 copies of each VM backup being retained at any given time. However my Backblaze B2 bucket size isn't reducing as the old backups are removed from the system.

I have the policy set to remove old files from the remote backup location, but it doesn't seem like this is being done based on monitoring .qdv files. How does the HBS backup job go about removing old files when they are part of dedup? Is there a pruning job I need to run?