Branched out replies are not visible in frontend

Hello,
whenever I branch out a reply as new question, I can see it listed in backend, but not in frontend, it's just not visible there.

Here are the exact steps I take:
- user post a reply to an existing question
- I click the "branch this reply as new question" button
- reply is being branched out correctly, and I am indeed redirected in frontend to new created question and can reply to it
- if I then go to the post list in frontend, the new created question is invisible (but I still see it in backend)

Forum is here: https://accademiainfinita.it/forum

Could you check this out?
Thank you