Using Slicers to filter visualisations with data from multiple fields

Hi,

can the same GCI Number be present for different years?

By design, in your model, when you filter on year and month, you filter the GCI Number in the table Branch Rev Data and then you filter the GCI List by CGI Number and with this list you filter data in the Import Data where it calculate the measure Count of Import files. This measure depends by the list of the GCI Number filtered in GCI List, not directly by Year and month in Branch Rev Data.

In my opinion you have to build in power query a new table Years, with distinct year values by the two raw tables and create two relationship one-to-many from this table to the raw tables and build the year slicer on this new table.