I came across a strange issue when exporting a polygon layer from AutoCAD Civil 3D to a shapefile.
The original AutoCAD drawing looks like this:
When loading it in to QGIS it looks correct:
But when I uploaded it to the GeoServer I got issues with the middle polygon (fully black). It looked like it moved a little to the south. Trying so solve this in QGIS I re projected it to a WGS84 layer (originally UTM 33N) but the problem stayed :
After extracting vertices I noticed the vertices of the middle polygon where the same for both layers so it had to bend?!
I did solve the problem by making a merged polygon layer (1 single polygon) of all the polygons in the shape file. Making a difference of it with a shapefile without the middle polygon and merging this with the shapefile without the middle polygon.