Muwatta Malik · Hadith 396

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَبْدَ اللَّهِ بْنَ مَسْعُودٍ، كَانَ يَدِبُّ رَاكِعًا ‏.‏

Yahya related to me from Malik that he had heard that Abdullah ibn Masud used to move forward while in ruku

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).