Hmm, that's strange. Is it a PDF opening directly in the native viewer, for example

https://www.jeffersonscher.com/temp/no-text.pdf

or is it a web page with an embedded PDF hosted in the site's own viewer?

I should add that just because it seems normal on Windows does not mean it will necessarily work normally on Mac. There could be a Mac-specific bug due to printing differences.

I'm using Integrasoft ERP (enterprise software). I've never had this problem prior to this update. I will say that 3 or 4 updates ago that the native PDF in Firefox Developer was generating fuzzy / blurry print output. It was resolved and now I have this.

My work around is to download the file and save/ view / print it in PDF.

My work around is to download the file and save/ view / print it in PDF.

Just to clarify, since I am not familiar with Integrasoft ERP, if the site is serving you a PDF, you can launch the PDF directly into your system default PDF viewer using the PDF viewer's download button. Here are screenshots for how that works in the native/built-in PDF viewer and a viewer embedded/hosted on a web page:

Native:

Embedded pdf.js viewer (hosted by the site):

I use native. Normally I would just hit the printer icon. Now I download and print.

I used to use Firefox ESR - but I lost functionality with it. The software provider's canned reply was and still is "we don't support IOS". So I switched to Firefox Developer.

Files that you direct to "Open in Firefox" are saved to the temp folder with some random name, so best is not to use this feature, but save the file directly to the hard drive and make sure you save the file with the correct filename.