Q: If I export the replica of a virtual machine (VM), does replication continue during the export?

A: Yes. The replica of a VM using Hyper-V Replica is in an off state and can be exported along with all its additional snapshots, if enabled. During an export, the replication from the primary continues, avoiding any possible degradation in continuity.

You might also look at "Configuring Hyper-V Replica in Windows Server 2012" and "Q: I've started to export a virtual machine (VM) in Hyper-V but I need to cancel the export. Which process do I need to stop?"