If you use Vial (https://get.vial.today) to configure your keyboard on macOS and you need to map a key to backtick/tilde, mapping it to the backtick/tidle key in the Vial keyboard won’t work (you’ll get the section/plus-minus key). Instead, map it to the following code:
KC_NONUS_BSLASH
(At least that’s what worked for me on the British English Mac layout.)
Right, realised why this was happening…
Had the virtual keyboard type set to ISO in Karabiner Elements while the external keyboard I have attached is ANSI.
You don’t need the above mapping if you set it correctly :)
@aral just curious, what keyboard do you use?