Why was the letter ya (ي) omitted from the word (بهاد) in Surat Ar-Rum, verse 53, but not omitted from the word (بهادي) in Surat An-Naml, verse 81?

The word "hādī" in the verse: "And you cannot guide the blind" is an active participle more eloquent than a verb. Its "yāʼ" is fixed according to grammatical rules because it is the root letter (lām al-kalimah), but the Uthmani script omits it, and this omission must be adhered to. Many similar instances exist in the Qurʼan where the Uthmani script deviates from the rules of Arabic orthography.