Currently on Gromit 58. Just noticed (and it may have been in previous versions of Gromit) that the font for the slide titles in Google Chrome are different to those shown in Firefox and Edge (both at latest versions on Win10 Pro 64-bit).
Browsers don't render fonts identically, pixel-for-pixel, but the differences are very small.
But if you're seeing something like the attached screenshot, you've got a simple browser cache issue. Either that, or you've got something set in Chrome that's blocking the loading of the Google font, and it's falling back to Verdana. The developer's console in the browser should reveal that problem - look at the "Network" tab, and check for 404's.
Your two original screenshots show two different renderings of the text. Enough to make me think that different fonts are being displayed. So unlikely to be due to a browser cache issue on both your machine and mine. I've deleted Chrome's cache to hell with its option to nuke everything anyway.
In Chrome developer, getting no 404 messages. All are at 200.
But having looked at the html and CSS, I now think that Chrome chooses a font from the CSS list in a different order from Firefox and Edge. Or I'm being incredibly picky in how the same font is rendered differently :^
In either case there's probably very little (if anything!) that you can do! I'm marking this as answered and will spend a bit more time testing. If I find anything else, I'll post back to this thread. Ta.