This usually happens because after you make each cut at the end of the long seams, a couple strips will kind-of wrap around from the end of one row and onto the next row because the end of each seam usually ends at the middle of the strip.
If you are talking about several
values of color conglomerating in one spot, I can't help you there
. I usually just add a border of a contrasting fabric and it balances everything out.