Bug when using field parameters to modify date fields in a "Before", "After" or "Between" slicer

[darrenfishell]

I am attempting to use Field Parameters to handle a common scenario to allow users to toggle between date filters using the exact date and filtering to the period of a specific date. 

I have a workaround, but wanted to flag what I believe is a bug in the preview feature (which is otherwise great)! 

Here's the relevant portion of my data model: 

I created this bridge table after getting an error I thought was caused by a Many-to-Many relationship from PERIOD_DATE[PERIOD_ID] -> 'DATE'[PERIOD_ID]. 

In my report, I've then configured a field parameter that toggles between 'DATE'[DATE] and PERIOD_DATE[DATE]. 

I would like to enable the slicer-to-slicer filtering, where one slicer selects the field used and the second slicer then displays the values of the selected field and allows the user to filter by the selected field. 

I am able to use this with a Relative Date filter with no issues, as follows: 

I am hoping to set this slicer instead to be either a "Before" or "Between" filter selection, to meet my reporting requirements. When I try to change the slicer using field parameter fields to a "Before" filter, I get the following error message. 

I believe that this filtering should work, given that the individual slicers using the relevant fields work as expected. 

[darrenfishell]

I have found another issue I believe is related. I've changed the field parameter to instead toggle between 'DATE'[DATE] and 'DATE'[MONTH_START] and I am getting a slightly different issue when switching to either "Between", "Before" or "After" filters -- it displays the fields in a hierarchy, which is not present in the data model: