Hi Alexander,
I moved to new version 26.5 and here my results:
Please see:
Comparison(left-Csv, right-ShapeFile)
image.png (179.0 KB)
Test data(input/output/QGIS)
5324-Csv-ShapeFile.zip (47.0 KB)
Thanks,... Comparison(left-Csv, right-Shapefile)...exactly match those in your CSV file; column names are case‑sensitive...