Yes i have, below is a snippet of DEBUG log:
[root] < POST
/ovirt-engine/api/vms/f9ec0eaa-1721-4114-a3b2-94fa6eca3f15/backups/10404c7c-1106-413b-9ced-bdd907e996a6/finalize
HTTP/1.1
[root] > <detail>[Cannot stop VM backup. There is an active image transfer
for VM backup]</detail>
[root] > <reason>Operation Failed</reason>
[root] > </fault>