i also can confirm this bug, i have the same problem after losing 20 fish on my survival while the ocelot showed hearts but was not tamed, i tried with 64 fish on a test world and it still didn't work.
i don't think there is a individual sound file for zombie babys so yeah i think this is normal
i confirm this bug, i gave a ocelot 64 fish, and i he did aprproach me, a lot of hearts but no tamed ocelot. in case it realy is extremely tricky that the average minecraft can't even get a cat in creative than i think that the hearts or the fact that the ocelot accepts the fish are bugs.