The affirmative passive third-person masculine paradigm preserves singular, dual and plural distinctions.
Word / formMeaning / explanation
Singular: يُفْعَلُhe is / will be acted upon.
Dual: يُفْعَلَانِthe two men are / will be acted upon.
Plural: يُفْعَلُونَthe men are / will be acted upon.
The plural ending is the same in active يَفْعَلُونَ and passive يُفْعَلُونَ. Their voice difference comes from the prefix and stem vowels, not from replacing the plural suffix.