It seems like normalize is overriding the body with font-family: sans-serif, instead of reboot's setting of $font-family-base
I think it's a duplicate of #21588
// Normalize includes `font: inherit;`, so `font-family`. `font-size`, etc are // properly inherited. However, `line-height` isn't inherited there.
But normalize doesn't inherit the font anymore.
Dupe of #21588.