PDF production issues when using Montserrat font in ArcGIS Pro 3.0.x in virtual environments about fonts HOT 1 OPEN

The "void spaces" are due to the overlaps being present in the static fonts.
Some text rendering engines are advanced enough to render static fonts with the overlaps (must be able to do this variable fonts).
Which is why it works fine in some applications (i.e. Chrome/Edge).

The embedding as a TTF fonts as a Type-1 is an Adobe Acrobat issue - which means they are probably using Acrobat Distiller to embed the fonts (my guess).
See: Why do OpenType fonts appears as Type 1 fonts in the Acrobat font list?

I assume you have control of what fonts to use... some options...

• The TTF releases in the font designer's repo have the overlaps removed - see here: v7.222
  and also includes OTF fonts - and OTF fonts do not have overlaps.
• Run the GF v8 fonts thru a tool to remove the overlaps (like FoundryTools-CLI)
• Convert the GF v8 fonts to OTF (which have no overlaps)
  again could use FoundryTools-CLI or various other tools, online, or font editors

from fonts.