The report concerning drawing a line in prayer when no physical screen is available is transmitted with multiple disputed forms of its isnād. The discussion mentions routes involving Abū ʿAmr ibn Ḥurayth, Ḥurayth, and Abū Hurayrah.
«إِذَا لَمْ يَجِدْ عَصًا يَنْصِبُهَا بَيْنَ يَدَيْهِ فَلْيَخُطَّ خَطًّا»
If he cannot find a staff to set before him, let him draw a line.
The chain variants are not uniform. The example shows how multiple materially conflicting, equally weighted routes may lead a critic to identify iḍṭirāb. Whether a particular specialist can ultimately prefer one route after considering further evidence is a separate evaluative question.