Unknown means the value in the table doesn't match with any value in the dimension.
Either the dimension has not been processed or the date table is out of sync with the dimension settings.
First to check if the date table is out of sync, run the sql query
select top 2 * from BIDATEDIMENSIONVALUE order by date desc
The first record will be the max date, the second should be the end date for the calendar.
If that record is not in the last year of your calendar as set on the date dimensions form, which appears to be set to 2025, then the date dimension data needs to be updated. you can update it by call BIDateDimensionManager::populateDateDimensions(false, true)
If the date records are present up to 2025, then the date dimension needs to be reprocessed.
For the processing step, there are a couple of different processing options. Incremental process is the default, but that only updates the measurements without reprocessing dimensions. You would ether need to use the full process option to reprocess your database to pick up the dimension changes, or else specifically reprocess the date dimension and choose to update dependent elements.
Hope this helps,
Lance