In Sahih Ibn Khuzaymah a route runs through ‘Asim b. Muhammad ← his father Muhammad b. Zayd ← Muhammad’s grandfather ‘Abd Allah b. ‘Umar, with the wording «فَأَكْمِلُوا ثَلَاثِينَ» (“complete thirty”).
It does not pass through Malik. Instead, a different chain reaches the same Companion, Ibn ‘Umar. Thus it is not a complete follow-up through Malik; it is a partial mutaba‘ah supporting the relevant instruction.
Here Ibn ‘Umar is Muhammad b. Zayd’s grandfather (and ‘Asim’s great-grandfather). Correctly preserving the father–grandfather links is essential: changing them would change the structure of the isnad being analyzed.