For a quick fix you could delete the corners and replace with the nice v shaped one I circled, If you deleted half of the border you would only have to manually fix 5 then mirror.(delete the two extra center ones) Or even a single "bump" manually aligned in the corners. Use the original vector as a guide (offset if needed). sometimes just changing the number of copies helps with corners.
The bottom point looks a little strange, probably because of number of copies as well, mirroring half of the design may help symmetry.