Nah it was definitely NVIDIA's fault. As you say there's nothing in the specs about alignment of those buffers, so they shouldn't be using aligned load instruct

Nah it was definitely NVIDIA's fault. As you say there's nothing in the specs about alignment of those buffers, so they shouldn't be using aligned load instructions. However Microsoft's malloc at the time was indeed returning 16-byte aligned buffers so they probably didn't notice it in internal testing.