### Primary Cluster Address Change

In Vault 1.4.0-1.4.3, a secondary cluster with a single `primary_cluster_addr`
configured will obtain the address of the active node in the primary cluster
via replication heartbeats from the primary cluster.

If the `api_addr` and `cluster_addr` in the heartbeats from the primary
cluster are not reachable from the secondary cluster, replication will not
work. This situation can arise if, for example, `primary_cluster_addr`
corresponds to a load balancer accessible from the secondary cluster, but the
`api_addr` and `cluster_addr` on the primary cluster are only accessible
from the primary cluster.

In Vault 1.4.4, we will use the `primary_cluster_addr` if it has been set,
instead of relying on the heartbeat information, but it's possible to
encounter this issue in Vault 1.4.0-1.4.3.