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This is usually an encodnig issues. Invalid characters in the string going into the xml. Remedy this by converting your string data into UTF8 when assining the data to your XML element.
Example:
XRecordDetail = New XElement(Header, System.Text.Encoding.UTF8.GetBytes(OriginalDataString))
Or
XMLData = XMLSystem.Text.Encoding.UTF8.GetBytes(OriginalDataString)
64bfe0e4-4d83-42ed-a1b2-596f46a1befb|1|1.0
VB.NET
XML