The asymmetrical unit cells in the Cell Map on Quad Mesh block are aligned in different orientations.
This occurs when there are one or more extraordinary vertices present in the Quadrangulate Mesh block, where the faces come together. An extraordinary vertex occurs when the edge count coming from a vertex is not equal to four. Generally, extraordinary vertices exist when surfaces of high angle curvature are present.
The helmet on the left contains extraordinary vertices while the helmet on the right does not.
This functionality may be available in the future. We recommend sticking to symmetrical unit cells until this is built into the block.
If the mesh does contain extraordinary vertices, then unit cells will not be consistently oriented. Also, lattices with asymmetric unit cells will be discontinuous. In this case, you can try using the Refine Mesh block with Refinement Steps = 1. If still inadequate, try Refinement Steps = 2. However, if you use this method to refine the mesh, the unit cells will be smaller.