Why does the source single out فِيهِ مُهَانًا?

Rules of Hāʾ al-Ḍamīr: Vowels, Ṣilah and Exceptions

• There is no hāʾ here
• It is not recited
• Ṣilah occurs despite the preceding sākin yāʾ
• It is about nūn assimilation