I suspect it return "Invalid token" response when you submit a new comment.

Currently we are not really sure why it return Invalid token but this is common case when the site has some extensive caching that caches the tokens, and the tokens was used to prevent csrf attacks.

By right, those cache system shouldn't cache those token on the page.

I didn't have this problem in komento 2.
You mean version 2 did not using token?

I just checked in Komento 2 code, it seems like you are right, that time we still haven't use that token yet.

In Komento 3, we already updated it.

You can check on this file :
JoomlaFolder/components/com_komento/views/comments/view.ajax.php

// LINE 47

KT::checkToken();

So maybe Joomla Team should care of it.
Thank you for your guidance

You're welcome.