Sunan Abi Dawud 816
سنن أبي داود#816HasanNarrated Mu'adh ibn Abdullah al-Juhani: A man of Juhaynah told him that he had heard the Prophet (ﷺ) reciting "When the earth is shaken" (Surah 99) in both rak'ahs of the morning prayer. But I do not know whether he had forgotten, or whether he recited it on purpose
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 2:426