getFeatures() delivers some fields more multiple times

Question

I am extracting data from selected fields using .getFeatures() in PyQGIS (see code below). The result is correct, but for some reason python delivers some features multiple times (see below; Lamu power project three times and Vipingo twice...). Any ideas why?

vectorLayer = QgsVectorLayer('C:/AIRPOLIM-ES/buf2.gpkg', 'buf2', "ogr")     
QgsProject.instance().addMapLayer(vectorLayer)

rasterLayer = popKE
QgsProject.instance().addMapLayer(rasterLayer)

zoneStat = QgsZonalStatistics (vectorLayer, rasterLayer , 'buf2_pop_', 1,QgsZonalStatistics.Sum)
zoneStat.calculateStatistics(None)

##extract results

for feature in vectorLayer.getFeatures():
    print(feature['Plant'],',',feature['buf2_pop_sum'])

Results:

Kaloleni Cement Plant , 22221449.12682629
Lamu Power Project , 22570960.33722942
Lamu Power Project , 22570960.33722942
Lamu Power Project , 22570960.33722942
Pokot power station , 40265891.87767924
Vipingo power station , 4560350.673526992
Vipingo power station , 4560350.673526992