I noticed today my backups have gone overboard on storage use, so I poked around a bit. It seems my backups retention setting was not being followed. I changed the toggle in Settings>Backup>Retention, changing to a longer date, then waiting a moment and changing it back... Immediately my backup server started purging the old snapshots that should have been purged before and overall usage is back to where I expected it (saved me 1/2 a TB in about 10 minutes lol).
If you have storage overuse issues, and you see in the folders for snapshots that some are older than should exist for your chosen retention period - then this might be just the fix you need... Turn it off and on again 😃