Checked on my phone, Chrome+Firefox work, WebKit (through wpe-android) doesn't. Safari and WebKit can't render this font for some reason, I suppose.
Did you read the explanation? It says right there on the page why it happens.
Or was that text added since you viewed it?
I probably didn’t read it. But I also had to read it twice to understand what it meant.
I’m still not sure if this is the mentioned issue or a different one.
Just glancing I would say it seems a bit different.
The only thing I'm seeing there is that line-wrapping might do [something], and a suggested workaround (which, oddly, they don't implement on the page). And the line-wrapping issue doesn't look like that to me, at least when I do it.