Tilestache doesn't serve polygons that are self crossed. like in the picture below.
I checked whether or not the polygon is stored within my postgresql, and it was the case. Therefore, the problem comes in serving, I kind of think that tilestache is not able to treat self crossed polygons. Any ideas ?
That is because a self crossing polygon is invalid in the OGC simple feature model. I can't think of a single program that will correctly display them.