أَوْ إِسْنَادٌ يَقَعُ إِلَى جَنْبِ إِسْنَادٍ لِعِلَّةٍ تَكُونُ هُنَاكَ؛
Or an isnād may be placed beside another because of a particular ʿillah present there.
A second chain may matter even when it conveys no new wording. Placing the chains together can clarify a question of transmission, such as the apparent connection of a route or a disagreement between transmitters.
Grammatically, «إِسْنَادٌ» is nominative and coordinated with the earlier «مَوْضِعٌ». It therefore introduces a second ground for justified repetition: a second chain may be needed for a particular critical reason, even without an added meaning in the wording.
“Because of an ʿillah present there” indicates a particular critical reason for the comparison; it does not declare every additional chain defective or guarantee that comparison proves a flaw. Its force depends on the evidence.