SOLVED

It looks like you're trying to use the `Max_Startdatum` variable as a filter condition for your chart, but you're encountering issues with the display of months on the x-axis when using this variable. You've also noticed that when you hardcode the date as `DATE(2023,9,1)`, it works correctly. The problem might be related to how the `Max_Startdatum` variable is computed.

Here's a potential explanation for the issue:

1. Data Type Mismatch:
- `Max_Startdatum` is calculated using `DATEVALUE`, which converts a date in text format to a date value.
- If the format of the date in your 'Booked_Times'[Startdatum] column is not consistent or there are data quality issues, it could lead to unexpected results when converting to a date.
- The hardcoded `DATE(2023,9,1)` is a date value, so there's no ambiguity in its format.

To troubleshoot this issue, you can try the following:

1. **Check Data Quality:**
- Ensure that the 'Booked_Times'[Startdatum] column contains consistent and valid date values.

2. **Display the `Max_Startdatum` Variable:**
- Create a card visual to display the value of `Max_Startdatum` and compare it with the hardcoded `DATE(2023,9,1)`. This will help verify if there are any differences in their formats.

3. **Debugging:**
- To debug the issue further, you can add temporary measures to your visualizations to display intermediate results. For example, create measures to display the month and year components of `Max_Startdatum` and `DATE(2023,9,1)` separately. This can help identify any discrepancies.

Here's an example of how you can create measures to display the month and year components:

```DAX
Max_Startdatum_Month = MONTH(Max_Startdatum)
Max_Startdatum_Year = YEAR(Max_Startdatum)
```

After adding these measures, you can add them to your visuals to see the month and year for `Max_Startdatum` and `DATE(2023,9,1)` separately. This should provide more insight into any differences between the two.

By following these steps, you should be able to identify the root cause of the issue and determine why `Max_Startdatum` is not producing the expected results for your chart.