Cleanup not working. Global quota 90%, but storage 100% use

Hello!

Cleanup not working.

Global soft filesystem quota: 90%
BTRFS storage: 100% use.

What I does wrong?

Server: UrBackup 2.4.13, debian 10.3 64bit / Linux 4.19.0-8-amd64);
Storage FS: BTRFS;

Screenshot:

Thank you!