how did you download these records? where did you download these records from? please provide an entire example record that you downloaded.
without that information i can only guess that you’re using Excel or some some other program to view the data in a tabular format, rather than viewing the data as raw text. when Excel converts the data upon opening, it will make some assumptions about how the data is formatted. in the US, thousands separators are commas and decimal separators are periods; whereas, i believe Germans will use periods for thousands separators and commas for decimal separators. so if you’re using something like Excel to view the file, you need to make sure you the thousands separator and decimal separator defaults match the format of the iNat CSV file; or else you need to explicity import the file into Excel to allow you to explicitly specify your thousands and decimal separators. see https://forum.inaturalist.org/t/csv-import-does-not-work/38169/13.