So I've done as you indicated and it would seem to be a bug in Proxmox.
root@blade7:~# ceph-disk list
/dev/cciss/c0d0 other, unknown
/dev/cciss/c0d1 other, unknown
/dev/cciss/c0d2 other, unknown
/dev/cciss/c0d3 other, unknown
/dev/cciss/c0d4 other, unknown
/dev/cciss/c0d5 other, unknown...