Minecart entities dissapearing

When the 1.4.2 update came i rushed to my zombie spawner and i purified the villager zombies. Then my plan was to take them to my base with minecarts . I brought one then broke the minecart. The villager disappeared,i relogged and searched everywhere when i gave up the villager was in the begining of the rail way. I hope you guys fix it ASAP because im planning to make an iron golem farm