Are all the Hadiths in "Al-Muwatta" and "Sunan al-Bayhaqi" authentic?

Al-Muwatta and Sunan Al-Bayhaqi are not entirely sound in all their hadiths. Al-Muwatta contains balaghat (reports of the Prophet's sayings without a complete chain of transmission), maraseel (reports by a Tabi'i directly from the Prophet without mentioning a Companion), mawqufat (reports from a Companion), and maqtu'at (reports from a Tabi'i). Ibn Abd al-Barr traced most of these and provided their isnad (chain of transmission), with only four hadiths remaining for which he could not. Al-Suyuti asserted that all maraseel in Al-Muwatta have corroborating evidence. Ibn Hazm mentioned that there are hadiths in Al-Muwatta which the majority of scholars deemed weak. As for Al-Bayhaqi, he sometimes mentioned weak hadiths, occasionally clarifying their weakness and other times not. He might also cite a weak hadith to refute it.