وَالتَّأْنِيثُ بِالْأَلِفِ الْمَقْصُورَةِ كَ«حُبْلَى» وَالْمَمْدُودَةِ كَ«حَمْرَاءَ» تَمْتَنِعُ صَرْفُهُمَا الْبَتَّةَ؛ لِأَنَّ الْأَلِفَ قَائِمٌ مَقَامَ السَّبَبَيْنِ: التَّأْنِيثِ وَلُزُومِهِ.
Translation: Words containing feminine alif maqṣūra, as in ḥublā, or feminine alif mamdūda, as in ḥamrāʾ, are diptotes without exception to this rule, because that alif stands for two causes: femininity and its inseparability.
Unlike the Hind case, these feminine alif endings do not require proper-name status.