Hey Tliebig,
While I am not entirely sure where the issue is, I will mention that I would go about accomplishing this task differently.
For “Datum”, I would parse that to be a normal date, IE the original date of 01-01-2024, 02-01-2024, etc. This will ensure it works fundamentally with the date picker. I would then click the little calendar button on the dimension “Datum” and change the data type to the year month data type.
This should ensure that it works with the Comparison date range.
Here’s a link to more date information.
Note: I would ensure that the “Date Range Dimension” is left as the “Date” data type, when you change it to Year Month it can get a lil’ funky.
Hope this helps
Dylan