Text/Fonts display poorly when printed to PDF format. Some letters look like a different font compared with others in the same word. Other letters appear to have a bold format compared with other letters in the same word/sentence.
The following option can be tried:
See Also
https://communities.bentley.com/products/microstation/microstation_printing/w/wiki/14255.when-creating-a-pdf-with-pdf-pltcfg-the-fonts-in-the-pdf-look-pixilated-and-not-rendering-correctly-when-zooming-into-the-pdf.aspx