Hadith specialists compiled dedicated studies of fathers-from-sons, sons-from-fathers, and multigenerational family transmission. Al-Khaṭīb al-Baghdādī collected unusual relationships such as fathers receiving from sons and Companions narrating from Successors.
Ṣalāḥ al-Dīn al-ʿAlāʾī gathered and classified chains of the form “someone from his father from his grandfather from the Prophet ﷺ”. Distinguishing the pronoun's possible antecedents is central to that work.
The methodological value lies in identifying people through corroborating chains and biographies. An unusual familial relationship is not, by itself, a verdict for or against the authenticity of a report.