For smart apostrophe, Unity fell back to fallback font despite that main font could've and should've rendered the character

I am using a font called Philosopher as my main font, falling back to Noto Serif Simplified Chinese as the fallback font. Almost everything works fine, until a smart apostrophe (single quote) appears. Now it appears as an apostrophe with a very long space after it. This is a quirk of Noto Serif Simplified Chinese. However, when I copy/paste the same string with same smart apostrophe into a TMP_Text (UI) with only my main font, it renders just fine. It seems that Unity is incorrectly falling back to the fallback font when it should’ve used the main font in this case.

After looking very closely, I realized that in the case of using Philosopher as the only font, versus Philosopher with Noto Chinese fallback, vs Noto Chinese fallback alone, the apostrophe (apart from the space) looked identical.

I theorized that the Philosopher doesn’t have the apostrophe font so maybe Unity fell back to some unspecified font (?) and somehow that unspecified font has an identical-looking apostrophe to Noto Chinese?

Anyway, I downloaded Noto Serif regular. I implemented fallback font as a 3-part series as follows: Philosopher, Noto Serif, Noto Serif Simplified Chinese. Now everything seems to work great! I still am not sure the cause of the original issue or whether it’s a bug in Unity.