Noticed a weird problem - some sites don't render their fonts, just empty space in place of text. Tried to debug it: 1. Safe mode and disabling hardware acceleration does… (read more)
Noticed a weird problem - some sites don't render their fonts, just empty space in place of text.
Tried to debug it: 1. Safe mode and disabling hardware acceleration doesn't fix it 2. Sandbox values don't change anything 3. Tried other Mac with the same Firefox version and macOS version - same issue 4. Experimented with CSS in dev tools - issue is related to the specific font (InterVariable in this case, also saw it with OpenSans before).
As you can see on screenshots - we have InterVariable font for this specific block. If I change CSS and remove this font, replacing it with some other one like Roboto - font starts rendering fine. Interestingly enough - font preview in the dev tools works completely fine - font renders, it just is not rendering in the page itself.
As it is a Variable font and me having older MacOS 10.11 - I was suspecting that it is a bug with Variable font support, but why does it render in dev tools and why doesn't it fall back to the other supported font, if this one is not rendered?
Disallowing pages 'to use their fonts' obviously fixes it - as it activates fallback to fixed fonts, but it is not a proper fix, as it obviously messes up designs for sites and their custom fonts.
This side renders completely fine in Chrome, so it must be a Firefox issue. Upgrading macOS is not an option, so I would be fine with a fixed ESR version that works correctly.
Attaching screenshots showing debug info.