A: Hyper-V Replica works by sending updates to the source virtual machine (VM) asynchronously every 5 minutes. In an unplanned failover where the latest updates couldn't be sent to the replica, a few minutes of state could be lost. This would push the domain controller (DC) back in time a few minutes, which is a huge problem, as it would cause the DC's Update Sequence Number to jump back, resulting in replication problems with other DCs and duplicate Security IDs for new objects. Microsoft has documented this at "Running Domain Controllers in Hyper-V."
For this reason, using Hyper-V Replica with DCs shouldn't be implemented. The bigger issue is, why would you want to? Active Directory (AD) has its own multi-master replication and site awareness, so for disaster recovery, if you just place a normal DC in the DR site that will stay synchronized, Hyper-V Replica isn't needed.
This is a great example of planning for disaster recovery. Always look at native capabilities of services, and use those first where available, then look at hypervisor features if no solution is available natively to the service.
