Al-Tirmidhi said:

“This hadith is mursal: ʿAbd al-Rahman ibn Abi Layla did not hear from Muʿadh ibn Jabal. Muʿadh died during the caliphate of ʿUmar ibn al-Khattab, and ʿUmar ibn al-Khattab was killed when ʿAbd al-Rahman ibn Abi Layla was a boy of six.

“This is how Shuʿbah narrated it from al-Hakam, from ʿAbd al-Rahman ibn Abi Layla. Yet ʿAbd al-Rahman ibn Abi Layla narrated from ʿUmar ibn al-Khattab and saw him.

“ʿAbd al-Rahman ibn Abi Layla was known by the kunyah Abu ʿIsa, and Abu Layla’s name was Yasar.

“It is reported that ʿAbd al-Rahman ibn Abi Layla said: ‘I met one hundred and twenty of the Ansar among the Companions of the Prophet, peace and blessings be upon him.’”

I say: This is also narrated in Abu Khaythamah’s Kitab al-ʿIlm (no. 21, in my edition); so refer to it.

As for the hadith of Ibn Masʿud:

Al-Tabarani narrated it in al-Saghir (2/91) and al-Awsat (7022), and through him al-Khatib narrated it in his Tarikh (3/399). Its chain contains weakness and a rejected discrepancy, due to Abu Taybah—namely, ʿIsa ibn Sulayman—for he attributed it to Ibn Masʿud, whereas it is the hadith of Muʿadh.

I have fully documented it in al-Rawd al-Nadir (635).

As for the hadith of Ubayy ibn Kaʿb:

Al-Nasaʾi narrated it in ʿAmal al-Yawm wa al-Laylah (391), through the route of al-Fadl ibn Musa, from Yazid ibn Ziyad, from ʿAbd al-Malik ibn ʿUmayr, from ʿAbd al-Rahman ibn Abi Layla, from Ubayy ibn Kaʿb, with similar wording.