Whenever I get out a piece of wheat, cows follow me like they are supposed to. However, they won't climb up one block. This is confusing because they will climb single blocks when left alone but won't while following you?

What I expected to happen was that cow would be able to climb one block in order to follow you like they usually do.

What actually happened was that the cow would not climb up one block and instead just kept jumping in front of the sod.

Procedure:

1. Find a cow.

2. Get out a piece of wheat.

3. Cow walk over to an area one block higher than you previously were.

4. Cow jumps in front of previous layer of ground instead of jumping up to where you are.