vSphere Replication 9.x
This is the expected behavior by design.
The replication schedule is automatically determined by the Recovery Point Objective (RPO) settings, which can range from 15 minutes to 24 hours (1,440 minutes).
vSphere Replication calculates its own internal schedule to distribute the load across the infrastructure and prevent resource contention. Consequently, there is currently no feature to schedule or force replication at a specific time.
vSphere Replication FAQ
https://www.vmware.com/docs/vmw-vsphere-replication-faq