Check the cluster logs from Primary and Replicas, during normal operating they will show messages as below:
Primary
From the https://primary_ip/admin | System Status/Settings | Cluster Management | Logs tab:
Gossip Client | Peer Console ReplicaName (IP_ADDRESS) replication status changed from Updating to Standby
Gossip Client | Peer Console ReplicaName (IP_ADDRESS) replication status changed from Standby to Updating
Gossip Client | Peer Console ReplicaName (IP_ADDRESS) replication status changed from Updating to Standby
Gossip Client | Peer Console ReplicaName (IP_ADDRESS) replication status changed from Standby to Updating
Replica(s)
From the https://replica_ip/admin | System Status/Settings | Cluster Management | Logs tab:
Cluster State Machine | Applying update bundle from PrimaryName (IP_ADDRESS)
Cluster State Machine | Applying update bundle from PrimaryName (IP_ADDRESS)
Cluster State Machine | Applying update bundle from PrimaryName (IP_ADDRESS)
Cluster State Machine | Applying update bundle from PrimaryName (IP_ADDRESS)
Expectations
The replica's /tpam is not accessible and this is expected. Replica's /tpam is only accessible only after failover.