To set the scene:
In the ArcGIS for Power BI visual, we connected to a hosted feature layer hosted on our ArcGIS Portal. This layer shows municipality boundaries and contains a unique ID for each one. In Power BI, a table contains this unique ID, as well as a numeric field with a population count.
Once the join layer has been setup through this unique ID, I added the population count and the map now shows the municipalties with a color classification based and label representing the population count as expected.
But this is where it goes wrong:
When I filter the dataset, certain municipalities are filtered away (as expected). However, the colors/labels do not change. Only when I make a change to the config of the join layer (does not matter what) and click "Update join", the labels and colors will match the current population counts based on the current filters. New changes after this are again ignored.
I assume this would be a bug? Or is there any workaround?

To provide some visual context. The "holes" on the map are municipalities which have been filtered out as expected. However, the summation of the population count (colors) can't be affected by filtering the report.