Filtering using date table not working how I would like

Filters and slicers don't affect calculated columns, they are only calculated once when the data is refreshed.

If you need the values to react to to slicers try doing it as a measure instead.

It looks like you might have defined this as a calculated column rather than a measure and calculated columns cannot be responsive to slicers since they are computed only when the data model is loaded or refreshed, not in response to user interactions or report settings like measures are.

Edit: brokencornets, it looks like johnt75 saw the same thing first so please mark their answer as the solution if you choose between us.