The normal low range copy does not have that, but the over all coloring is not as good as this fused version. Any idea what causes that in the fused version and how to fix it?
Another possibility is that neighbouring images overlap so much that, despite A being largely to the left of B, some parts of remapped A are off to the right of B, again giving them the chance to appear in the final composite when they should be covered up (this isn't likely in your single row pano).
Putting the images in shot order or overlapping a little less could stop the first case happening. Or you could use <a href="http://horman.net/multiblend">multiblend</a> ;)