Is what is stated in the book "Ta'wil Mukhtalif al-Hadith" regarding the hadith "If a fly falls into a vessel, immerse it" — where it is sometimes considered absurd and other times a sound hadith — a contradiction or a lack of understanding on the part of the reader?

The hadith (definition) is authentic according to Ibn Qutaybah and Bukhari, and Al-Khattabi, Al-Nawawi, Ibn Hajar, and Al-Shawkani have all concurred on its authenticity. Perhaps Ibn Qutaybah mentioned his initial statement as a نقل (narration/report) from the Mutakallimun (scholastic theologians).