Release Management 2013 Server Web Site throwing "Data at the root level is invalid..." error after applying RM 2013 Update 4

Question

I upgraded our RM Server from 2013 Update 2 to Update 4. During smoke testing, I discovered that the RM approval website would get stuck and display a loading wheel when showing the list of releases. After rebooting the server and uninstalling and reinstalling,
I eventually got it to load the web site just fine, however the windows event log is displaying thousands of instances of the same error (about once a second).
Timestamp: 4/2/2015 2:25:05 PM
Message: Data at the root level is invalid. Line 2, position 1.: \r\n\r\n   at System.Xml.XmlTextReaderImpl.Throw(Exception e)
   at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
   at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace()
   at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
   at System.Xml.XmlTextReaderImpl.Read()
   at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options)
   at System.Xml.Linq.XDocument.Parse(String text, LoadOptions options)
   at Microsoft.TeamFoundation.Release.Common.ExtensionMethods.XmlExtensionMethods.ToXDocument(String value, Boolean preserveWhitespace)
   at Microsoft.TeamFoundation.Release.Common.Helpers.WebServiceHelper.ExtractWebMethod(String pathInfo, Stream inputStream)
Category: General
Priority: -1
EventId: 0
Severity: Error
Title:
Machine: [Server Name]
Application Domain: /LM/W3SVC/2/ROOT-1-130724725961138960
Process Id: 3448
Process Name: C:\Windows\SysWOW64\inetsrv\w3wp.exe
Win32 Thread Id: 1136
Thread Name:
Extended Properties:
This is quite concerning because it leads me to think something else is wrong.  I read somewhere else that .Net Framework 4.5.1 is required for RM, but the system requirements on MSDN don't mention that.  Any help greatly appreciated.
Specs:
RM Server: Windows 2012 R2
Release Management 2013 Update 4
Connect to TFS Server 2013 Update 2
We are not using HTTPS:

Answer 1

Hi Joe519,
Thanks for your post.
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