I'm seeing a difference between the kerning for variable fonts.
I've captured these two images to show the differences, Google fonts: Montserrat and Josefin Sans. Both fonts are identical size and kerning settings, but the BOLD versions of these fonts show the X and A closer together (alongside other issues, notice the closeness of the 'T's), it appears to be a problem with vairable fonts files only.
I was using the Google fonts repo inside my Fonts on the newer machine, however after looking into it further my older machine uses separate .ttf files versus the Google fonts repo (https://github.com/google/fonts) which uses [wght].ttf files.
I've managed to transfer the original .ttf files from my old machine that I need, but wanted to flag to the Affinity team since the Google Fonts github repo and website provide these problematic [wght].ttf and similarly other websites with variables fonts files as default.
I tested the issue with another variable font: (https://github.com/github/hubot-sans)
> For anyone facing a similar issue, you can download the family of fonts from Google Fonts and they provide a 'static' folder where you can use the individual .ttf files.