The adjectives vipariṇāmin and aññathābhāvin rarely in the Early Buddhist texts. (Try the search terms “aññathābhāvin*” and " vipariṇāmin*".) According to the Pāḷi grammars at my disposal, the forms vipariṇāmino and aññathābhāvino can occur modifying nominative plural nouns only in the masculine. However the given adjective forms occur modifying nominative, neuter, plural nouns rūpā and phoṭṭhabbā.
How can this be?