Nerd Font used to have a 'ligature removal' feature for the Nerd Font Mono fonts.
This seems to be broken with recent fonts (i.e. v2.2.2 seems ok while HEAD is broken).
See also

• Hasklug ligature issue #934
• Hasklug: additional ligature issues #973
• Fira Code Nerd Font Mono is not displaying == sign correctly #975

The reason is the recent fix of the ligature removal code (i.e. 5d218b1).

History data:

• Ligature removal introduced 02-2018 (v2.0.0) 9917e2d
• Ligature removal broken 08-2018 (v2.1.0) 0a480bb
• Ligature removal fixed 09-2022 (v2.3.0-RC) 5d218b1

Fonts with ligature table data:

• Arimo (*)
• Cousine
• DejaVuSansMono
• FiraCode
• FiraMono
• Hasklig
• Iosevka
• Lekton
• Monoid
• Noto
• OpenDyslexic (*)
• Overpass
• ShareTechMono
• SpaceMono
• Ubuntu (*)

The tables have been added with a2f5620 and never been updated (which would generally be needed if the source font is updated) (except Hasklug 12cd703).

Affected (very quick check) is only FiraCode and Hasklig.

Updated after introduction of the ligature removal are

• FiraCode 78be0e1 d23d0e0 338497d 2d32a1f dfc31db d9ea69a ad162ac
• Hasklig e2745c3 ca44d38 6edb957
• Iosevka a7d8f51 052ece3 8738eb4 09c4776 6edb957

Of the three Iosevka's ligature removal seems to have survived the updates, but maybe not.