Comment ça se fait qu'il faille se subjonctif avec cette construction?

Sorry, typo: "Comment ça se fait qu'il faille Le subjonctif avec cette construction?"

Hint: "fait que"

Thank you, Christopher. I googled the expression and found this: http://bdl.oqlf.gouv.qc.ca/bdl/gabarit_bdl.asp?id=3650 However, I have the impression that it is mostly the first case (faire que + indicatif) that is applicable here. Is it because it is a question that it turns into subjonctif?

I'm not a teacher but I would say because it expresses doubt/uncertainty. One of the triggers for subjunctive is the lack of certainty (but there are always exceptions. It's covered a lot in the B2 level tests. Other triggers are emotions, necessity, possibility, wants/desires. You can find great examples here and on https://www.lawlessfrench.com/.

Thank you, Christopher, for the link to https://www.lawlessfrench.com. I found many interesting things there! Just not the answer to my question. But I'll keep searching... :-)

I would not lose sleep over the subjunctive if you're not at an advanced level. It's not always evident because there are many situations that cause it to be used. French speakers will know when you missed one and they will praise you when you get it right. I've been working on it for 5 years and it's just now starting to make sense to me. For now all you need to know is there has to be a "que" and from that you should add one of the conditions that requires subjunctive until you master that particular condition. Kwiziq is great at teaching this as it will do exactly what I described above. For example, in my current tests I've been drilled repeated on il faut que to the point I dream about it. I still don't quite understand your original question, it's not clear what you're asking is causing the subjunctive but just the fact that it's posting a question implies uncertainty which normally requires subjunctive. Good luck