While I was playing around with Excel 2013, I noticed some inconsistency in the way slicers behave depending on whether they are used to filter a PowerPivot table, or whether they are used to filter a traditional pivot table.
With traditional pivot tables, slicers do not affect drill-through if they are applied on hidden fields. In other words, if you use a slicer to filter Field1, then you must place Field1 somewhere in your table (row, column, or page) in order for the drill-through to behave as expected.
This is not the case with PowerPivot tables. Drill-through works as expected.