The current browser renders like this:
Expected:
A string has the following characters:
<p>A B</p>
Notation: HTML
The font has a substitution (inside the liga feature of
the font):
sub A' B by C;
Notation: OpenType Feature File Specification
If the characters render next to each other the first character is replaced by the ligature feature of the font. See OpenType Docs (Microsoft) – Registered features.
The renderer therefore shows:
If the string gets formated in CSS with
.red { color: red; }
Notation: CSS
<span class="red">A</span><span>B</span>
Notation: HTML
The current browser renders like this:
Expected:
If the string gets formated in CSS with
.bug-active::first-letter { color: red; }
Notation: CSS
<p class="bug-active">AB</p>
Notation: HTML
The current browser renders like this:
Expected:
Screenshots taken on real devices
Safari 12.0 (14606.1.36.1.9) on MacOS 10.14
Apple TextEdit 1.14 (340) on MacOS 10.14
Firefox 61.0.2 on MacOS 10.14
Adobe InDesign CC Version 13.1 on MacOS 10.14