Making the holes that close to the edge has dictated where the thread will lay. The stitching appears to be too close to the edge and some of the prick marks are actually making contact with the edge itself.
It looks like the leather is made up of multiple layers, so I assume the total thickness is quite high. You may want to use a pricking iron as a marking tool, then finish with an awl. Otherwise a fully penetrating pricking iron is going to make overly large holes as seen in the top of the image. Pricking irons have a tendency to migrate towards the edge as you hammer them through, as the weaker side offers less resistance. This effect gets worse the closer to the edge you start.
Making the holes that close to the edge has dictated where the thread will lay. The stitching appears to be too close to the edge and some of the prick marks are actually making contact with the edge itself.
It looks like the leather is made up of multiple layers, so I assume the total thickness is quite high. You may want to use a pricking iron as a marking tool, then finish with an awl. Otherwise a fully penetrating pricking iron is going to make overly large holes as seen in the top of the image. Pricking irons have a tendency to migrate towards the edge as you hammer them through, as the weaker side offers less resistance. This effect gets worse the closer to the edge you start.