Qiyās concerns recognized patterns of formation; samāʿ concerns usage actually transmitted from authoritative speakers. A surprising-looking form should not be condemned without considering both.
The word-level definition uses morphological irregularity as a distinct defect. To analyze a given form responsibly, identify its underlying word, the applicable rule, and reliable usage.
Explaining the plural of būq or the assimilation in mawaddah is more precise than merely calling the form “strange.”