eastcoaster99

Thank you so much!! I will do that. 
 

Was this document created by importing a PDF?
Because none of the text has a Font Style assigned.
The Font Name field is selected, but the Font Style field is blank.
You need to assign the Font Style to each piece of text.
I did this for the front page by assigning Bold, and the PDF then showed the correct font.
You should probably use some text styles, which would make this easier.

Hmmmm ... I see nothing ... wonder if that is a font replacement issue at my end.
I have Josefin Sans installed, but my Avenir Next is a different version (LT Pro).
Another idea - do you have the variable font also installed?
Because when an application does not support variable TTF fonts,
the default master is what appears for every weight.
And the default master in that variable font is Thin.
So that would appear for every weight.
Like you have in your PDF.
I assume you got the fonts from Google Fonts.
Google Fonts insists that the variable font family name and the named instances are the same as the static font names (so the statics will work as a fallback).
This causes name conflicts when both the variable and statics are installed.
So you cannot have both installed at the same time.
Is that the case?
 

Ahhh ... that's the problem.
You have the variable font installed (JosefinSans-VariableFonts-wght.ttf).
Affinity apps do not yet support variable fonts.
The Mac font manager fools you by displaying the variable instances as if they will work,
but there is no variable font support yet.
So what you actually get is the default master in the variable font - which is Thin.
Un-install the variable font(s), and install the static fonts.
Then it should work.
 

This may be because of an issue with the PostScript Name field inside the fonts.
When this is configured incorrectly, wrong fonts may get embedded (which changes the look).
You can confirm the wrong fonts by looking at the PDF embedded fonts.
Can you attach the PDF and/or the document?
What fonts are you using?

Do you have Embed Fonts set to All Fonts as well as the Subset Fonts box checked under More in the PDF Export dialogue window?

Thanks LibreTraining. Here's one example of a document that loses the font style. In this example, I'm using Josefin Sans Bold and it gets exported as Thin. I've attached both the Affinity file and the PDF.  It happens with other fonts as well - today was Roboto that changed after export. 

I'd be grateful if you can let me know anything I can do here to help solve this! Thanks so much. 
Checklist PDF.afpub Checklist PDF.pdf