A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
The best way to get attention on this from MS is to provide a detailed repro case so they can reproduce the results at their end. They don't generally watch this forum but we can get the info to them.
So please do the following:
Produce a small PPTX file using the same font as you're currently having issues with, save the file with fonts embedded and also take a screenshot of the slide using the fonts, add a new blank slide and add the screenshot to it. Result: one slide that uses the fonts, another slide that's just an image of the first slide so anyone who opens the file can compare what you're seeing (the image) with what's happening to the fonts (the regular slide).
It'd be helpful if some of the text on the first slide includes the full current PPT version and your MacOS version, along with the full name of the font in question.
Pop the resulting file onto dropbox/OneDrive/etc and reply here with a link to it.