Hi,
and thanks for making an excellent app! The documentation is also really well written.
I recently made a free programming font available here:
…and tried to follow the steps in the guide describing style linking, so that the Bold is the Bold of Regular, and the Bold Italic is the Bold and Italic of Regular.
A user noticed that in some apps on Linux, the Bold style appears Bold and Italic: Why is the 'Bold' variation is italic? · Issue #11 · rubjo/victor-mono · GitHub
Incidentally, PHPStorm on macOS will only list a single entry for the font.
While investigating, I came across another (possibly related) issue. In PHPStorm on macOS, bold + italic seems to become doubly italic:

Does any of this look familiar? JVM-related in some way, maybe? Any hints on how to remedy these issues?