The "bred_all_animals" advancement is the only place where the word "breed" is spelled "bred", while its localization strings are "advancements.husbandry.breed_all_animals.title" and "advancements.husbandry.breed_all_animals.description", its description is "Breed all animals!", and the advancement for the first animal to breed is "breed_an_animal".
Thus, the advancement should be spelled "breed_all_animals".
Can confirm in 1.18 Pre-release 4.