The font that couldn't spell te reo
A Māori-design brand we build for writes te reo across their whole site, product names included, so macrons are not an edge case for them, they are the brand. Their headings had a persistent wrongness on words like Māori and pēpi that everyone had half-noticed and nobody could pin down. The macron sat visibly off to the right of its vowel, floating toward the next letter.
What we found
The usual suspects were all innocent. The HTML carried properly composed characters, so it was not an encoding problem. The font supplied its own macron glyphs, so it was not a fallback font sneaking in. The weights were real files, so it was not synthetic bolding distorting anything. What was left was the font itself, and rendering the same word through nine typefaces side by side proved it. This one face draws its macron vowels with the accent offset to the right, outside the letter’s own box, at every weight. It is simply how the glyph was drawn.
There is no setting that fixes a glyph. The brand’s headings moved to a face that draws macrons where they belong, and the body text followed for consistency. Kupu Māori now sit correctly everywhere on the site.
What to take from it
If your brand writes te reo, or any language beyond unaccented English, the font choice is a functional decision and not just an aesthetic one. Type a handful of real kupu with tohutō into a font’s preview before committing to it, at more than one weight, and look hard at where the accents land. It is a thirty-second check, and skipping it can leave your brand misspelling its own language in a way no amount of configuration will undo.