Sitecore with SolrCloud throws HTML tags error - sitecore

Question

We recently setup SolrCloud (Solr 4.10.3) with Sitecore 8.0 Update 2. We have also set it up so that it allows for Switch on Rebuild using this patch - https://github.com/SitecoreSupport/Sitecore.Support.449298/releases.
The setup works fine in one environment but in another environment it is throwing a strange error in the second environment. Some of the indexes rebuild fine but other indexes fail with the following error -
Job started: Index_Update_IndexName=Sitecore_web_index|#Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Xml.XmlException: The 'br' start tag on line 1 position 133 does not match the end tag of 'body'. Line 1, position 177.
at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
at System.Xml.XmlTextReaderImpl.ThrowTagMismatch(NodeData startTag)
at System.Xml.XmlTextReaderImpl.ParseEndElement()
at System.Xml.XmlTextReaderImpl.ParseElementContent()
at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader r)
at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader r, LoadOptions o)
at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options)
at System.Xml.Linq.XDocument.Parse(String text, LoadOptions options)
at SolrNet.Impl.SolrBasicServer`1.SendAndParseHeader(ISolrCommand cmd)
at Sitecore.ContentSearch.SolrProvider.SolrBatchUpdateContext.AddRange(IEnumerable`1 group, Int32 groupSize)
at Sitecore.ContentSearch.SolrProvider.SolrBatchUpdateContext.Commit()
at Sitecore.Support.ContentSearch.SolrProvider.SwitchOnRebuildSolrSearchIndex.Rebuild(Boolean resetIndex, Boolean optimizeOnComplete) in D:\works\projects\gitHubRepo\Sitecore.Support.449298\src\Sitecore.Support.449298\ContentSearch\SolrProvider\SwitchOnRebuildSolrSearchIndex.cs:line 155
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
at (Object , Object[] )
at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
at Sitecore.Jobs.Job.ThreadEntry(Object state)
At first look, it looks like the error may be related to some corrupt BR tags without closing slash at the end. But where should I look is not clear.
Also, another issue is that after this happened, the content editor, index rebuild, and other interfaces have started failing with the same error.
Any help is appreciated.
Thanks