It is my experience that cracks that do break the brick itself are pretty strong cracks. Cracks that stair step down the brick wall going on the mortar line are fairly common in the summer and winter, especially when you do not water the foundation properly during long periods without rain.
BC is correct, you have some sort of ground, foundation failure that is causing one part of your home to sink at a faster rate than the other and its not bending, but just breaking.
Patching the crack by the builder was just so so so cosmetic and will do nothing but hide the crack for a short period of time.
Now, since your home is new, I would go through the warrenty program, taking pictures and documenting every word said and all forms sent to you. This is so important. even the stupid thing that the builder did.
Not to cause you concern, but if its doing it now when new, guess what will happen later on?
Now, I live in my 30 year old brick home and it does the same, but only on the mortar lines. instead of using mortar, they make latex mortar in a caulking tube that works great and expands and contracts with the seasons. It actually dries concrete or mortar color.