Welcome to StarWind Forum and thank you for your post. I will raise the internal request to look into the possible causes. I might reach out back to you for additional details.
As a workaround, try converting a disk to a VM.
P.s. I think you can just copy VMDK to oVirt and create the VM in place.
Welcome to StarWind Forum.
Yes. You can connect the storage to the VMs via iSCSI Initiators inside the VMs (please note that you still need traffic separation according to best practices). Let me know if you have more questions.