Many Error 5605 WMI Errors “Access to the root\mscluster namespace was denied”

Getting a lot of these on my SQL Server cluster (SQL 2008 on Windows 2008), mostly on the inactive nodes. I have Googled a bit and found nothing really helpful.

Access to the root\mscluster namespace was denied because the namespace is 
marked with RequiresEncryption but the script or application attempted to 
connect to this namespace with an authentication level below Pkt_Privacy. 
Change the authentication level to Pkt_Privacy and run the script or 
application again. 
8/9/2010 6:05:32 AM 
Error Microsoft-Windows-WMI 
Error code: 5605 
Eventlog: Application

Note: I did lock down security about this time on these Servers, making the SQL Server Service Account (MYDOMAINSQLAcct) not an admin on the box anymore but giving it proper local security policies to run the cluster per Pro SQL Server 2008 Failover Clustering (Apress) by Allan Hirt (see chapter 5 "Service Accounts, Domain Groups, and Rights" p.186).

Local Security Policy                     SQL Server

Adjust memory quotas for a process
(SeIncreaseQuotaPrivilege)                Yes           

Bypass traverse checking
(SeChangeNotifyPrivilege)                 Yes           

Log on as a batch job (SeBatchLogonRight) Yes           

Log on as a service (SeServiceLogonRight) Yes           

Replace a process-level token
(SeAssignPrimaryTokenPrivilege)           Yes    

My first instinct is to make MYDOMAINSQLAcct an admin again and see if these go away… rule that out or in, at least. But this won't really solve the problem since I don't want my service account to be an admin on the box.

I am getting these errors every 5 minutes and they seem to be almost entirely on my "B" or passive nodes.