This behavior is caused by formatting settings applied to the image in the Word template. If the image (such as a signature) is configured to overlap and move with text, it may render incorrectly, appearing flipped or mirrored during the PDF generation process used for email merges.
To resolve this, remove the image and reinsert it as a static image using Paste or Insert. Make sure that both Move with text and Allow overlap are disabled. With these settings adjusted, the image will render consistently in both Word print merges and PDF email attachments, without requiring any additional configuration or dynamic merge fields.