The issue is that you have an even number of chevrons on one side meeting up with an odd number on the other. The chevrons are not going to meet up the same. As mentioned above, you can add cornerstones. Another option would be to interrupt the side with the 41 patches. have 20 chevron patches, one plain peach colored patch, then 20 more chevrons. This way, you take the odd chevron off on the end. I've done a couple of BH pieced borders and have found that she often puts an odd block in the middle to make the pattern come out in the corners.