title: Multiple runs on docx4j generate unexpected results
body: <p>I have an application which consists of a simple html page with a text input. This text input relates to a database identifier, in order to fill some templates.</p>
  
  <p>The document I'm filling is only a page, with a title, and a table with data, populated with the data obtained from the query with the identifier.</p>
  
  <p>It works properly for the first document I ellaborate, but the second one does not: on the second and consecutive runs, the table just disappears.</p>
  
  <pre><code>WordprocessingMLPackage wordMLPackage = WordprocessingMLPackage
              .load(new File(inputFile));
  VariablePrepare.prepare(wordMLPackage);
  /* I ellaborate a HashMap&lt;String, String&gt; called mappings from the results
  obtained from the database here */
  wordMLPackage.getMainDocumentPart().variableReplace(mappings);
  wordMLPackage.save(new File(outputFile));
  </code></pre>
  
  <p>inputFile and outputFile are simple strings containing the paths to the files.</p>
  
  <p>I found out several "winword.exe" processes run simultaneously, and they do not shut down when the execution ends. In addition, I keep getting a popup saying that "normal.dotm" has changed and prompts me to save the changes. Could this be related?</p>
  
  <p>Any help would be appreciated.</p>
  
  <p>Thanks in advance.</p>