Long story short, one of my two DC's crashed. I used metadata cleanup on the other DC to manually remove the crashed DC. After rebuilding the machine, I DCpromoed it back into the domain, and everything appears to be functioning correctly, except for the following that it popping up on one of the DCs (The one that didn't crash)
Event Type: Error
Event Source: NTDS Replication
Event Category: DS RPC Client
Event ID: 1411
Time: 10:17:45 PM
User: NT AUTHORITY\ANONYMOUS LOGON
Active Directory failed to construct a mutual authentication service principal name (SPN) for the following domain controller.
The call was denied. Communication with this domain controller might be affected.
8589 The DS cannot derive a service principal name (SPN) with which to mutually authenticate the target server because the corresponding server object in the local DS database has no serverReference attribute.
If I look at the GUID that the error is reporting, I'm pretty sure that this GUID is the old identifier for the DC that crashed. If I look in the _msdcd folder in DNS, there is no reference to this GUID anywhere. This is why despite the error, the directory seems to be working fine.
How can I clean this up?