Cleansing does not work properly

I start the command “urbackupsrv cleanup --amount 0%”
So all Linux Backups are cleaning.
But not the Windows Images. Why?

The log says:

2018-12-19 16:14:24: Backup destination cannot handle subvolumes and snapshots. Snapshots disabled.
2018-12-19 16:14:24: Cleaning up 0 percent
2018-12-19 16:14:24: Cleaning up 0 bytes on backup storage
2018-12-19 16:14:24: Database cache size is 1 GB
2018-12-19 16:14:24: Starting cleanup…
2018-12-19 16:14:24: Freeing database connections…
2018-12-19 16:14:24: Enough free space now.
2018-12-19 16:14:24: Enough free space now.
2018-12-19 16:14:24: Client with id=3 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=442, backuptime=2018-12-07 23:26:58, path=/export/backup/urbackup/pdc/181208-0026_Image_C/Image_C_181208-0026.vhdz, letter=C: ) from client “pdc” ( id=3 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Client with id=3 has 6 incremental image backups max=6
2018-12-19 16:14:24: Client with id=6 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=459, backuptime=2018-12-08 23:41:31, path=/export/backup/urbackup/sammelserver/181209-0041_Image_C/Image_C_181209-0041.vhdz, letter=C: ) from client “sammelserver” ( id=6 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Deleting full image backup ( id=466, backuptime=2018-12-09 00:41:12, path=/export/backup/urbackup/sammelserver/181209-0141_Image_D/Image_D_181209-0141.vhdz, letter=D: ) from client “sammelserver” ( id=6 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Client with id=6 has 6 incremental image backups max=6
2018-12-19 16:14:24: Client with id=1 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=461, backuptime=2018-12-08 23:42:07, path=/export/backup/urbackup/acc/181209-0042_Image_C/Image_C_181209-0042.vhdz, letter=C: ) from client “acc” ( id=1 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Client with id=1 has 6 incremental image backups max=6
2018-12-19 16:14:24: Client with id=2 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=463, backuptime=2018-12-08 23:57:26, path=/export/backup/urbackup/app/181209-0057_Image_C/Image_C_181209-0057.vhdz, letter=C: ) from client “app” ( id=2 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Client with id=2 has 6 incremental image backups max=6
2018-12-19 16:14:24: Client with id=5 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=465, backuptime=2018-12-09 00:14:43, path=/export/backup/urbackup/DATABASE2016/181209-0114_Image_C/Image_C_181209-0114.vhdz, letter=C: ) from client “DATABASE2016” ( id=5 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Deleting full image backup ( id=467, backuptime=2018-12-09 00:42:34, path=/export/backup/urbackup/DATABASE2016/181209-0142_Image_D/Image_D_181209-0142.vhdz, letter=D: ) from client “DATABASE2016” ( id=5 ) …
2018-12-19 16:14:24: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:24: Client with id=5 has 6 incremental image backups max=6
2018-12-19 16:14:24: Client with id=7 has 2 full image backups max=1
2018-12-19 16:14:24: Deleting full image backup ( id=469, backuptime=2018-12-09 01:39:51, path=/export/backup/urbackup/exchange/181209-0239_Image_C/Image_C_181209-0239.vhdz, letter=C: ) from client “exchange” ( id=7 ) …
2018-12-19 16:14:24: Deleting image backup ( id=516, path=/export/backup/urbackup/exchange/181212-0248_Image_SYSVOL/Image_SYSVOL_181212-0248.vhdz ) …
2018-12-19 16:14:24: Deleting image backup ( id=517, path=/export/backup/urbackup/exchange/181212-0249_Image_C/Image_C_181212-0249.vhdz ) …
2018-12-19 16:14:25: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:25: Client with id=7 has 6 incremental image backups max=6
2018-12-19 16:14:25: Client with id=4 has 2 full image backups max=1
2018-12-19 16:14:25: Deleting full image backup ( id=472, backuptime=2018-12-09 18:04:09, path=/export/backup/urbackup/fileserver/181209-1904_Image_C/Image_C_181209-1904.vhdz, letter=C: ) from client “fileserver” ( id=4 ) …
2018-12-19 16:14:25: Cannot delete image because incremental image backups referencing this image are not allowed to be deleted
2018-12-19 16:14:25: Deleting full image backup ( id=470, backuptime=2018-12-09 17:58:36, path=/export/backup/urbackup/fileserver/181209-1858_Image_D/Image_D_181209-1858.vhdz, letter=D: ) from client “fileserver” ( id=4 ) …