Http2 connection reset vault

I installed a 3-node vault server in Kubernetes using the helm chart with SSL enabled for external addresses with a valid certificate. Vault is constant logging the following:

http2: server: error reading preface from client read tcp> read: connection reset by peer

vault-server-0 is having a connection reset with vault-server-1.
Vault is working. Also vault-agent in consul is using 100% of CPU allocated (0.5) all times.
Is this a problem with the SSL connection between the vault servers?

Ok, the problem is HA proxy ingress has some problem with the self-generated SSL connection to the backend. I will experiment another ingress because HAproxy is powerful but complex to config for my simple use case.