Filter a report using query string parameters in the URL - not working for some fields

Hi Everyone,

I tried to add ?filter=Table/Field eq 'value' at the end of my report URL that I've uploaded to Power BI Service (report is published to premium App space), and found that this did not work for the field I wanted, but did work for another one.

The field I want does not have a space in the string, but it is displayed in a synced slicer on the same page.  When I publish the report to the Service, I already have a (different) value pre-selected in this sync slicer.  I'm wondering if that has something to do with the error (i.e. the slicer did not change to my desired 'value' when I re-loaded the URL with the ?filter... at the end). 

When I tested this with a different Field not contained in a slicer, this ?filter... feature worked fine.  

Am I missing something here or is there a work-around?  Is the problem that the field is contained in a sync slicer (or a slicer in general) on the page?

Thanks!