Hello,
“The problem is, I set Level 2 schedule - Incremental Backup, Expires after 7 Day(s).”
This means the Incremental Forever is working as designed.
IE: Incremental backups do not expire.
YOUR SOLUTION:
In the UI, go to Montor > Disk Storage > Disk Storage Backups
From here you can select backup jobs and delete them from the Arkeia Index.
NOTE: This does not remove the block from the pool.