Cannot delete storage policy in vCloud Director 5.5

I'm trying to delete storage policy in vCloud Director 5.5. I did it in multiple vCloud Director organization VDCs but stuck with one on the same vCloud Director instance. I migrated all VMs, vApp templates and media to another storage policy. I checked in vCenter that there is no VMs that belong to that policy. Still in the vCloud Director, I see 30MB "requested" from this storage policy for this VDC.

Any ideas what else I should check? How can I find what still uses this storage policy?