SnapVault destination volumes not reflecting source volume snapshot reserve

CDOT 8.3.1P1

We have a 4 node cluster with a mixture of SSD, SAS and SATA disks.

Production data is stored on the SSD and SAS disks.

We are using SnapVault to keep backups of the production data on the SATA disks.

It all seems to be working OK but if I look at the space allocation for the SnapVault destination volumes, they all have the snapshot reserve set to 0% even though the source volumes have non-zero values.

Is this a feature or a bug?

Thanks.