SCCM/WSUS issue after importing March CSA patch bundle

Question

Hi, I am having an issue with security patch deployment since Tuesday night.  Debugging is ongoing.  I am running SCCM 2012 CU2.
Coincidentally, the problem appeared shortly after importing the March XP CSA (Custom Support Agreement) patch bundle into SCCM.  From the client end, WUAHandler.log reported continuous failures/retries.  On lower-end machines, system performance
became very poor.  From the server end, starting up the Windows Server Update Services mmc (yes, I know you're not supposed to be doing anything in here, which I'm not) results in a connection error.  The detailed error message is shown further down.
It was difficult to get the client machines to stop "thrashing" per WUAHandler.log.  It wasn't until I de-installed/re-installed WSUS and ASP.NET that things quieted down yesterday afternoon.  All appeared to be stable until this morning
when I  re-added "Windows XP Custom Support" under the SUP Component Properties tab, imported the CSA bundle info, initiated a CAB synchronization from Microsoft, and re-enabled Software Updates on the clients. 
Again, I would get the error when starting up the Windows Server Update Services mmc.
I am doing everything again, but this time one step at a time.  My working theory is that there is some kind of corruption caused by the CSA import (this worked just fine up until Feb.).  A few hours ago, Microsoft published a new CSA
patch bundle because a patch was apparently forgotten.  Is it possible that there was some kind of corruption included with the original bundle published on Tuesday?
I will post what I find as a result of my debugging.
Thanks,
Nick.
The WSUS administration console was unable to connect to the WSUS Server via the remote API.
Verify that the Update Services service, IIS and SQL are running on the server. If the problem persists, try restarting IIS, SQL, and the Update Services Service.
The WSUS administration console has encountered an unexpected error. This may be a transient error; try restarting the administration console. If this error persists,
Try removing the persisted preferences for the console by deleting the wsus file under %appdata%\Microsoft\MMC\.
System.IO.IOException -- The handshake failed due to an unexpected packet format.
Source
System
Stack Trace:
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
   at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   at System.Net.ConnectStream.WriteHeaders(Boolean async)
** this exception was nested inside of the following exception **
System.Net.WebException -- The underlying connection was closed: An unexpected error occurred on a send.
Source
Microsoft.UpdateServices.Administration
Stack Trace:
   at Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer(Object[] args)
   at Microsoft.UpdateServices.Administration.AdminProxy.GetUpdateServer(String serverName, Boolean useSecureConnection, Int32 portNumber)
   at Microsoft.UpdateServices.UI.AdminApiAccess.AdminApiTools.GetUpdateServer(String serverName, Boolean useSecureConnection, Int32 portNumber)
   at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.GetUpdateServer(PersistedServerSettings settings)
   at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.ConnectToServer()
   at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.ConnectToServerAndPopulateNode(Boolean connectingServerToConsole)
   at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.OnExpandFromLoad(SyncStatus status)

Answer 1

Yes, WCM.log showed the same 503 error starting on the Wednesday morning at 2:53am, and I also noticed wsuspool had stopped. My most noticeable symptom was the thrashing of wuahandler.log on the clients, causing poor system performance on machines with 2gb
of memory. Multiple de-installs/re-installs of WSUS failed to clear the issue until we increased the memory setting in IIS.
Nick
WCM.log:
System.Net.WebException: The request failed with HTTP status 503: Service Unavailable.~~   at Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer(Object[] args)~~   at Microsoft.SystemsManagementServer.WSUS.WSUSServer.ConnectToWSUSServer(String
ServerName, Boolean UseSSL, Int32 PortNumber)  $$<SMS_WSUS_CONFIGURATION_MANAGER><03-11-2015 02:53:26.225+240><thread=30872 (0x7898)>
Remote configuration failed on WSUS Server.~  $$<SMS_WSUS_CONFIGURATION_MANAGER><03-11-2015 02:53:26.226+240><thread=30872 (0x7898)>