ضَرَبَ غُلَامُهُ زَيْدًا
His servant struck Zayd.
Here غُلَامُهُ is the grammatical subject, while زَيْدًا is the object. The pronoun in “his servant” refers to Zayd, yet precedes Zayd both in word order and in the grammatical precedence assigned to subject versus object.
The point is not that a pronoun's antecedent must invariably come earlier in the sentence. The fault is this particular precedence in both wording and rank, which illustrates weak composition.