Is this a behavior with a particular PDF or with all the PDF? Try printing a different PDF and check.
What is the workflow or steps you are doing to print the PDF file?
Could you please share a screenshot of the printed page that is unreadable? Also, if its a file specific issue please share the sample file with us via private message for testing. Click on the message icon on the top right corner of the screen to start the private message.
Try printing the PDF as image. Go to Print > Advanced > Print As image > Click OK and check.
You may also try to open the PDF in Google chrome. Right Click > Select, Open with Chrome and try to print from there.