My understanding is the “serving size” field should just contain a number and the unit, in this case “62 g”. But for this product it contains “62 g (Valeurs nutritionnelles moyennes pour 1 portion de 62 g)”. How are applications using OpenFoodFacts data supposed to parse that? Unfortunately that information was provided by the manufacturer so it cannot be fixed…
Should be fixed, but I don’t know if non-moderator users can change manufacturer-provided data…
As a non-moderator user myself, the answer is no: non-moderator users cannot change such data.
Information identified by a factory icon has been provided by the manufacturer. It can be changed only by the manufacturer and moderators. If it is out of date or incorrect, please let us know.
So thanks for fixing the information for this product.
Related issue on the android app bug tracker: Add support for showing producer provided and protected fields · Issue #5430 · openfoodfacts/smooth-app · GitHub
This is not actually fixed 
Sorry for my late reply.
In fact there is nothing to fix: you should rely on the serving_size field (which is ok), not on the serving_size_imported. The later cannot be modified, even by a moderator/admin, because it is an imported value from the producer.
I don’t know about these fields: in the Android application (4.18.1) all I see is “Taille d’une portion" : “62 g (Valeurs nutritionnelles moyennes pour 1 portion de 62 g)”.
So based on your reply it looks like the Android application only shows the “serving_size_imported” field whereas the website shows “62 g” which would match the “serving_size” field.
So maybe the issue is that the Android application is showing the wrong field. At least the inconsistency between the website and the Android application is questionable.