Event ID 4768 with X509N:<S>CN=HPC Pack 2016 Communication

In a Windows only, Domain join environment, we are constantly getting these event log messages on our domain controllers:

```
Event ID: 4768
A Kerberos authentication ticket (TGT) was requested.

Account Information:
Account Name: X509N:CN=HPC Pack 2016 Communication
Supplied Realm Name: [DOMAIN].COM
User ID: NULL SID

Service Information:
Service Name: krbtgt/[DOMAIN].COM
Service ID: NULL SID

Network Information:
Client Address: ::ffff:[IP ADDRESS OF HEAD NODE OR COMPUTE NODE]
Client Port: 52448

Additional Information:
Ticket Options: 0x40810010
Result Code: 0x6
Ticket Encryption Type: 0xFFFFFFFF
Pre-Authentication Type: -

Certificate Information:
Certificate Issuer Name:
Certificate Serial Number:
Certificate Thumbprint:

Certificate information is only provided if a certificate was used for pre-authentication.

Pre-authentication types, ticket options, encryption types and result codes are defined in RFC 4120.
```

We were originally using the self-signed certificate for the headnode/compute node communication. But in an attempt to correct these audit failure messages, I generated a certificate from our active directory certificate authority, and went through the steps to change the head node and compute nodes so that they use this new, fully trusted certificate. This doesn't seem to have made any difference.

I'm not even sure why these servers would need to authenticate with the domain controller -- is there any way to get these errors to stop?