Hi Alexander,
I moved to new version 26.5 and here my results:
Please see:
Test data(input/output/QGIS)
shapefile8.7z (7.5 MB)
Please make conversion in your side from Shapefile to Kml and test it in your side in …...using var shp = VectorLayer.Open(@"C:\Data\input.shp", Drivers...KML (optional, for testing) shp.Save(@"C:\Data\output.kml", Drivers...