I'm using parameters to allow users to filter report data based on allowed values in a dropdown. A blank value means 'don't filter' in the DAX behind. As an example (not the actual report)
Note that allow blank value is selected.
In available values, I add a few, one of which is blank:
This works fine in the report builder; I can run the report and choose anything from the dropdown and the filters are correctly applied. However, when the report is published to the Power BI service, while the dropdown item with the blank value is displayed, it is not selectable. If it is the first item in the list, then the filter is applied correctly, but if the user selects another item, then tries to select 'All' again, there is no response. The other items continue to work. The same problem happens if the blank item is elsewhere in the list.