Rolling 4 Quarters Based on Slicer Selection

Hi everyone, I've been stuggling to figure out a solution and hoping that someone in this community could point me in the right direction.

End Goal: Table/Matrix the displays only data for Last 4 Quarters based on slicer selection

• I found the following post here, and was able to implement for my situation and it is mostly working: link 
  • Summary: use a disconnected date table and a flag measure to flag the last four quarters. Then, use a visual level filter and the flag measure to filter for only for quarters with "Y" as these are the last four quarters

Here is the measure I'm using to flag the last 4 quarters:

Issue: This approach doesn't seem to work when there are rows added to the matrix from other tables - ie a location table. 

• See attached pbi file for example of the issue: pbi example - google drive 
• The first matrix shows the R4 quarters, which is how this should work
• The second matrix includes the location code, which causes the R4 quarter flag filter to no longer work
• I imagine that there is something in the DAX of the R4 quarter flag that is cuasing the rows to override the column filter, however, I am not able to figure out what is causing this

It would be so appreciated if anyone is able to provide any suggestions how to make this work when there is row data as well. Thank you in advance for your help!