I marked this “always”, but perhaps “usually” is right. After I print a document, the page layout is changed because of the font management (I think). The resulting layout leaves paragraphs extending beyond window margins.
Try this in your mailbox.
Set your Fonts setting to Large Fonts
Open a mail message that has a couple of long paragraphs.
Note page layout
Print the page
Note the page layout is changed.
Screen shots:
Font Settings
Before printing
After printing.