In my survival world y try to have ocelot's babys and llama's wanderin babys, but after feed it, their babys despawn when i go far away of them

What I expected to happen was...:
I expected they didn't despawn

What actually happened was...:
they despawn after few minutes when i go more of 128 block of them and wait

Steps to Reproduce:
1. i did a prove in creative, i feed a two ocelots or llama's wanderin
2. i waited a one minute in 128 block aprox far away of them 
3. when i came back, ocelots and their baby despawn

pd: only the ocelots despawn when i didn't domesticate them