«فَإِنْ غُمَّ عَلَيْكُمْ فَأَكْمِلُوا الْعِدَّةَ ثَلَاثِينَ»
If visibility is obscured, complete the number to thirty.
Al-Shafi‘i's version contains this explicit wording. Some other transmissions from Malik contain «فَاقْدُرُوا لَهُ» at the corresponding point. The difference led some scholars to regard al-Shafi‘i as singular in transmitting this particular formulation from Malik.
The investigative question: Did no other pupil of Malik report that expression or support its meaning? This cannot be decided by merely reading one available chain in one compilation.