´Narrated Ibn 'Abbas:` from 'Ubayy bin Ka'b, that the Prophet (ﷺ) would recite: "Qad Balaghta Min Ladunni 'Udhra" (18:76) with heaviness (Muthaqqalah - meaning with Tashdid on the Nun in "Ladunni")."
Hadith ReferenceSunan at-Tirmidhi / Chapters on Recitation / Hadith: 2933
Hadith Gradingالألبانی:ضعيف الإسناد //، ضعيف أبي داود (856 / 3985) // | زبیر علی زئی:(2933) إسناده ضعيف / د 3985