Mobs trapped in Minecarts are able to leave them when you exit and re-enter the game, this causes extreme annoyance or overengineering of breeding machines and some kinds of farms.
Developers showed interest in fixing this issue in the past.
Related issues
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Then, MC-814 should be re-opened as it´s not working.
Si estan aqui por elrich, comenten! xD
para tu granja de animales autamatica de survival 1.3(1.4)
no?
Duplicate of [MC-814]