يَعْلُو طَرِيقَةَ مَتْنِهَا مُتَوَاتِرٌ فِي لَيْلَةٍ كَفَرَ النُّجُومَ غَمَامُهَا
Successive showers struck along her back in a night whose clouds concealed the stars.
Mutawātir means continuous or successive. In kafara al-nujūma ghamāmuhā, the verb kafara has the lexical sense of covering or concealing.
The rainfall against the animal’s back and the clouded sky together establish darkness and disorientation. The description is not a theological use of the verb.