I have run into an issue that I'm not sure how to correct. What happens is that in some subjects the surfaces don't seem to properly track sulci coming off the medial part of temporo-occipital cortex. Please see green arrows on the attached image. 

In fact the tutorial on topological defects shows an image with a similar issue, but fixing it is not discussed.

http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/TopologicalDefect?action=AttachFile&do=get&target=TopoafterBM.jpg

I have checked and these are sulci and not the occipital extent of the lateral ventricle.

Perhaps it is not a problem, or if it is then how to approach fixing it?

Thank you,

Darren