New text box contains text from an existing textbox

[Jack]

When inserting a text box, text in an existing box appears in the new text
box (Text boxes have been copied/pasted in the document).
How can I get rid of this problem?

 

[Stefan Blom]

This is a sign of document corruption. For more on document and template
corruption, see http://word.mvps.org/faqs/apperrors/corruptdoc.htm.