You have a backup plan applied to a Hyper-V replica VM, where the backup agent is installed only on Hyper-V replica target host (no agent on source host).
After updating to Acronis Cyber Cloud v.8.0, you are getting the following alert from this plan triggered after some time:
Backup is missing: No successful backups for X days
In version 8.0, the methods to uniquely identify Hyper-V VMs and their corresponding Hyper-V replicas, have been changed, since these types of VMs natively have the same ID in Hyper-V WMI infrastructure (by Microsoft design of Hyper-V Replication) which caused the Acronis Cyber Cloud to fail to distinguish between these VMs (they were considered as single entity) when both replica source and replica target Hyper-V hosts were discovered.
To solve the issue, Acronis backup agents are now assigning new unique IDs to Hyper-V replicas in version 8.0 (after update), however the existing backup plans applied to Hyper-V replicas still refer to old IDs and thus are causing the errors.