Le problème vient des non-dits

[Basler Biker]

I had this one wrong ??

But there are 2 possibilities, I think

• le problème vient du non-dit
• le problème vient des non-dits

I am sure LeFigaro asked "des" ... but you can't go "back' so they ask again, as it's a random question...
https://leconjugueur.lefigaro.fr/ukexojour.php

But what is the real expression. Singular or Plural?
If you get this exercise on the daily LeFigaro, be sure to double check this, whether it asks "du" or "des"