Which browser, and version of, are you using?
James, this happens on all browsers on Windows 10 for me – I checked in Firefox (v70), Chrome (v77) and Edge, on two machines.
On Mac the fonts render nicely, without this weird ‘bold’ upper case characters. On Windows they’re not bold bold, but enough to look strange (as in the screenshot)
So it seems to be something off with the font rendering on Windows 10 at least?
Interesting! I don’t have a Windows PC to test from myself, but I used BrowserStack to check under Windows 10 with Edge 18 https://cld.wthms.co/MG62g9 Firefox 69 https://cld.wthms.co/mPZG9N and Chrome 77: https://cld.wthms.co/jgyhiR
These all look fine.
BrowserStack doesn’t do any of the rendering on my local machine, it basically just screenshares the browser, so I don’t think this is an all-Windows problem necessarily.
Do you have access to another Windows PC to test from?
Strange. It happens on the two Windows machines I have access to, but I don’t have any others I can check.
I’m not a Windows guy myself, but maybe re-install the affected fonts?