Selection Date Slicer

m_wex , As slicer might be coming from Date table having only one-directional join. Then Date slicer will not filter.

You can add measure in visual level filter for slicer and check for not blank value 

You can force QTD

QTD QTY forced=
var _max = today()
return
if(max('Date'[Date])<=_max, calculate(Sum('order'[Qty]),DATESQTD('Date'[Date])), blank())
//or
//calculate(Sum('order'[Qty]),DATESQTD('Date'[Date]),filter('Date','Date'[Date]<=_max))
//calculate(TOTALQTD(Sum('order'[Qty]),'Date'[Date]),filter('Date','Date'[Date]<=_max))

LQTD QTY forced=
var _max = date(year(today()),month(today())-3,day(today()))
return
if(max('Date'[Date])<=_max, CALCULATE(Sum('order'[Qty]),DATESQTD(dateadd('Date'[Date],-1,year)),'Date'[Date]<=_max), blank())
//OR
//CALCULATE(Sum('order'[Qty]),DATESQTD(dateadd('Date'[Date],-1,Quarter)),'Date'[Date]<=_max)
//TOTALQTD(Sum('order'[Qty]),dateadd('Date'[Date],-1,Quarter),'Date'[Date]<=_max)

or

LQTD QTY forced=
var _max1 = maxx('order',[Order date]) // or //maxx(allselected('Date'), 'Date'[Date]) // or // Today()
var _max = date(year(_max1),month(_max1)-3,day(_max1))
return
if(max('Date'[Date])<=_max, CALCULATE(Sum('order'[Qty]),DATESQTD(dateadd('Date'[Date],-1,Quarter)),'Date'[Date]<=_max), blank())
//OR
//CALCULATE(Sum('order'[Qty]),DATESQTD(dateadd('Date'[Date],-1,Quarter)),'Date'[Date]<=_max)
//TOTALQTD(Sum('order'[Qty]),dateadd('Date'[Date],-1,Quarter),'Date'[Date]<=_max)