Font weight keeps changing in Powerpoint

I have a recurring issue where the font weight keeps changing on Powerpoint slides when switching between slides, or interacting with text.

I am using a Mac, with Ventura 13.0.1 installed. I am using Version 16.73 of Powerpoint.

I am using Work Sans, downloaded an installed as a .ttf from Google Fonts through the Mac Font Book.

My issue in particular is that the text that I set as Work Sans Regular keeps changing to Work Sans Medium, either individual words or whole text boxes of text. Sometimes I find that interacting with the text in any way (such as adding or removing a hard return, selecting text, making a change and undoing) will turn that particular sentence from Regular to Medium. If I paste text into a text box containing only Work Sans Regular, and choose "Keep text only", it also reverts to Work Sans Medium.

I have set up the master pages using either Work Sans Light, Regular or Semibold, never Medium. Yet it reverts back to Medium.

Uninstalling Medium as a weight is not a good option as I frequently have to work across powerpoints as well as many other types of assets where I might need to use Medium.