Threaded Comments Weta Child

Hi there, I’ve noticed a very strange behavior on my Weta Child Theme. Threaded comments are enabled in the settings and should be supported by Weta. I didn’t change anything related to comments from the original css/php files, except for the font family and size, but threaded comments only show correctly if made directly from the dashboard by an administrator.

If you, as a new user, try to reply to a comment on the site, your comment will inevitably show un-nested at the bottom of the list. Is that intentional (only administrators can reply to existing comments) or it’s a bug? How can I change that, allowing threaded comments for anybody? You can test it here:

Many thanks for the support.