Cannot add date slicer (from/to) with "Cal Year / Month" BW Date object

Hello,

In SAP Analytics Cloud I'm using a live connection to SAP BW 7.4 (yes, that is possible ;) )

From my BW query I want to create a date slicer input control (filter by Range) in my dashboard, based on a BW date dimension "Cal Year / Month" of type DATS. Looks straight forward. But we get the error message popup window: "Failed to Intialize" as soon as I select the dimension "Cal Year / Month" for the Input Ctrl.

Has anyone seen this before?

Tx,

Jan