Auto_join using IPs which are not compatible with Let's Encrypt certificates

We are trying to deploy a Vault cluster using auto_join to our VSphere cluster.
We are connecting to VSphere and Vault is discovering the other nodes and getting back the node names and IPs but then tries to use the IP to join the node. It then throws an error saying the certificate does not have a IP SAN for the given IP.
This is a problem as we are getting our Certificates from Let’s Encrypt using the ACME provider in Terraform and as far as we can tell there is no way to add IP SANs in the Terraform ACME provider and Let’s Encrypt does not seem to support IP SANs.
Is there a workaround to this or are we missing something?

To expand these are internal private IP addresses which you can’t add to a real certificate.
Ideally we would want it to use the nodes fqdn