PowerPoint to PDF fonts colour is wrong

I'm trying to export a PowerPoint document to PDF. I'm using foxit reader. When opening the PDF document the colour of the fonts changes from white to black (in the ppt I'm using white fonts, Arial).

I tried other things like Save as, or Print, or Embed fonts in the file and few more but none of it worked.

I am using the latest version of Foxit and PowerPoint.

In the end, I installed Acrobat Reader and the fonts were ok (white). Any idea why Foxit changed the fonts colour and how could I fix this?

Windows 11.