Baby zombie horses cannot be fed to grow up faster

feeding a baby mob its preferred food makes it produce green particles and increase its Age tag, however that doesnt happen with the baby zombie horse

Steps to produce:

1. spawn a baby horse by typing /summon minecraft:horse ~ ~ ~ {Age:-10000}

2. spawn a baby zombie horse by typing /summon minecraft:zombie_horse ~ ~ ~ {Age:-10000}

3. feed the normal horse 15 golden carrots

4. feed the zombie horse 15 red mushrooms

5. see which of them became an adult

Expected behavior: both horses produce green particles each time they are fed and eventually become adults

What actually happens: only the normal baby horse produces green particles and becomes an adult, the baby zombie horse stays a baby