Sorry, Low337, the poster corrected his OP with:
"Yes, you guys are right in what you're explaining."
The pitcher apparently did not STEP, but jumped with both feet, the front foot leaving the ground a bit before the pivot foot. It was not a step with one foot, then after it is grounded, stepping with the other.
This is a legal jump turn or jab step.
What you are describing is definitely a balk, and not such a clever one. It is commonly called in my neighborhood.