Safari not using kerning pairs

Now that I’ve upgraded to Glyphs from Glyphs Mini, I’ve started some (premature) work on kerning pairs for Putterbubble, a font for Quikscript. Since the character for [ð] could stand to be much closer to a subsequent character for [ɪ], I decided to start there first.

Once I tested the font in Safari using @font-face, though, it didn’t seem to work even though I have html { text-rendering: optimizeLegibility } in CSS. It’s fine in Firefox, though, and I have another font called Kingsley that manages to be handled properly by Safari. (Since Kingsley’s letter for [ð] is angled from the baseline to the x-height, I look at the last two letters of “Putterbubble”

AFAIK, kerning support in browsers is still highly problematic. Have you sent the files to support at this domain?