Zombies can hit villagers through blocks, when the zombie is beneath them

Hi, I saw a fix somewhere that said mobs now have their hit range fixed, so they can hit above them. I think this has affected my zombification system. I have a zombie in a Minecart, the level below my villagers. I had leaves blocking the zombie from the villagers and used to just punch out the leaves of the villager I wanted zombie. This was working fine before the fix. Now, the zombie can hit the villagers up and through the leaves. So I changed them for trapdoors. The zombies can hit through them too. So I changed the block to glass, but same story. Finally I just tried wool but he can still hit my villagers when they are sleeping, or just close to the back wall. I don't get hit by the zombie, even if I stand right next to them.