Just swap your quarter and your table calc date fields on columns and LoD, as attached.
The area chart is behaving badly because it needs all the marks to be aligned on the same dates in order to draw properly - which works if you use quarter on columns, but not if you use the individual dates.
I also added sheet 3 with reference lines at the very first and last quarters, which just keep the axis scale fixed, so you can see more clearly that the filter is behaving itself.
Thanks for the response. I guess it makes sense that all the dates have to line up across the marks.
I can solve this probably by generating records with a value of Zero for the measure, when a record doesn't exist, for the level of dimension that I'm looking at. I had been hoping to get out of having to generate these empty zero records, but it looks to a requirement at this point.