When ocelots chase chickens or when wolves chase skeletons or sheep they jump towards their target without testing if they can land where they are jumping to.
- Build the setup as shown in the attachment below: setup.png (2 blocks with 3 blocks of air in between)
- Summon a chicken or sheep on the diamond block, and an ocelot or a wolf on the emerald block.
Sometimes the ocelot or wolf jumps into the gap between the blocks
The following is based on a decompiled version of Minecraft 1.10 using MCP 9.30.
This happens probably because the method net.minecraft.entity.ai.EntityAILeapAtTarget.shouldExecute() does not test if at the position where the mob is supposed to leap to is a block.