Layer keys not working as replacement in Key overrides

[Wanyann]

When i setup Key override using layer keys as replacement, for example, TG(4), and i press overrided keys, keyboard doesn't toggle 4'th layer, but simply types character "" for some reason.

Screenshot of bugged Key override:

About Vial:
Vial 0.7.1

Python 3.6.8
Qt 5.9.3