Keydown event triggered two time after enter Korean letter.

[yomapi]

When editing with Korean characters, I found that one more character was entered at the end.
This problem was not found in the Alphabet. As a result of some debugging, it was confirmed that the keydown event triggered two time when Korean characters were entered. Is this event related to Korean characters being entered twice?
If so, Can I get some hint?
Thanks.

keydown.mov

[yairEO]

I honestly don't know. You can clone Tagify's source code and debug using npm start command and then open /test/basic.html in your browser, and debug the onInput event callback