That can happen, for example, when images are styled to avoid to be broken by a page break. PD4ML forces a pagebreak to protect an image, but if there is a text block below the image top edge and the text already printed on the current page – it will also be repeated on the next page.

A good practice to avoid the problem is to use conditional page breaks or to enclose content portions to table cells and to apply “page-break-inside: avoid” style to the table rows.

See: http://pd4ml.com/cookbook/conditional_pdf_page_breaks.htm