Using Microsoft Word styles is the best way to create consistent and well-formatted documents. Even if you don't apply Styles to your Word Documents, Microsoft will automatically default to its "Normal" Style.
Styles are located in your Home tab ribbon, and if you click any part of your Word document, it will show what Style you're using:
Make sure your Normal Style matches with the Font style and size your document has to avoid any formatting issues when drafting documents.
When you draft a document and see that your Automation fields change Font style and size, it indicated that your "Normal" Style is not matching with your Document Font style and size:
How to edit your Normal Style
Click Style Pane
Click the down arrow next to Normal
Change the Formatting
Save the template back to your Collection ( floppy disk icon on the top right of the side task panel)