Hi there,
It's Stuart here from the BackupAssist team, thanks for posting on our forum.
Are you backing up the actual
physical host running the Hyper-V role? If so, then what you're seeing is normal as you're unable to restore a host machine within a guest as it's not possible to run the Hyper-V role within a guest. If that's the case, then what you're seeing is expected.
As for your second comment, I'd need to see the actual backup report and also know the specific configuration you have for Hyper-V in your environment to be able to answer.
Are you running any form of clustered environment?
Are you running any form of deduplication on the source data?
Are the VM's reporting as being backed up online or offline? If so, is this different to those which are displaying the data?
When you check the monitor screen during a backup, is there anything abnormal with those guests?