Hi,
When using curl to get e.g. leader info (api /v1/sys/leader) among data returned there is leader_address in ip format like “leader_address”:“http://10.10.11.10:8200”. Leader_cluster_address is returned as fqdn, so would it be possible and does it make sense to return leader_address as fqdn too? Ip is not of much use, especially if something should happen to pod 
The leader address is the redirect address, which should come from you configuration’s api_addr (or redirect_addr in the storage or HA storage block if provided that way). Can you check whether the api_addr is in your config file an IP address?
All data is being “fed” by statefulset and its template has api_addr defined as:
https://github.com/hashicorp/vault-helm/blob/master/templates/server-statefulset.yaml#L78
Fix IMHO would be to rewrite that line to be like the vault_cluster_addr that currently returns fqdn
https://github.com/hashicorp/vault-helm/blob/master/templates/server-statefulset.yaml#L88