The book gives صَيَاقِلَةٌ and فَرَازِنَةٌ as forms accepting final hāʾ / tāʾ marbūṭa, and explicitly calls them fully declinable.
They therefore admit tanwīn and take kasra in the genitive, unlike the listed ultimate broken-plural forms.
This is a contrast under the author's precise rule, not a claim about every feminine noun or every plural.
Opening interactive controls...
Diptote Causes — Ultimate Broken-Plural Patterns
The book gives صَيَاقِلَةٌ and فَرَازِنَةٌ as forms accepting final hāʾ / tāʾ marbūṭa, and explicitly calls them fully declinable.
They therefore admit tanwīn and take kasra in the genitive, unlike the listed ultimate broken-plural forms.
This is a contrast under the author's precise rule, not a claim about every feminine noun or every plural.