Filebeat include_lines regex

Filebeat does not recognize many regex patterns?

For example this works ^.\b(System.moduleDown|was thrown)\b.$ in regex101 but when used in filebeat it does not work, can someone please explain, why or how to debug?

I want to avoid using greedy search, is there any alternative?

<?xml version="1.0"?>
<Data xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <ConversationId>445655767</ConversationId>
  <SeverityLevel>Error</SeverityLevel>
  <Time>2020-01-17T14:55:02.9720399-07:00</Time>
  <MachineName>test_223</MachineName>
  <ComponentName />
  <TypeName>superHost</TypeName>
  <Operation>UnhandledException</Operation>
  <LogMessage>exc Exception: Exception of type 'System.moduleDown' was thrown. 
Exception Stack:    at System.Collections.Specialized.ListDictionary.set_Item(Object key, Object value)
   at System.Collections.Specialized.HybridDictionary.set_Item(Object key, Object value)
   at System.ComponentModel.PropertyChangedEventManager.AddListener(INotifyPropertyChanged source, String propertyName, IWeakEventListener listener, EventHandler`1 handler)
   at System.ComponentModel.PropertyChangedEventManager.AddHandler(INotifyPropertyChanged source, EventHandler`1 handler, String propertyName)
   at MS.Internal.Data.PropertyPathWorker.ReplaceItem(Int32 k, Object newO, Object parent)
   at MS.Internal.Data.PropertyPathWorker.UpdateSourceValueState(Int32 k, ICollectionView collectionView, Object newValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.ClrBindingWorker.AttachDataItem()
   at System.Windows.Data.BindingExpression.Activate(Object item)
   at System.Windows.Data.BindingExpression.AttachToContext(AttachAttempt attempt)
   at System.Windows.Data.BindingExpression.AttachOverride(DependencyObject target, DependencyProperty dp)
   at System.Windows.StyleHelper.GetDataTriggerValue(UncommonField`1 dataField, DependencyObject container, BindingBase binding)
   at System.Windows.StyleHelper.GetChildValueHelper(UncommonField`1 dataField, ItemStructList`1&amp; valueLookupList, DependencyProperty dp, 
</Data>

Thanks