Hi Alexander,
I moved to new version 26.5 and here my results:
Please see:
Comparison(left-Csv, right-GeoPackage)
image.png (173.1 KB)
image.png (164.8 KB)
Test data(input/output/QGIS)
5331-Csv-GeoPacakge.zip (3…...of the CSV header (the first line) and the exact code you are...