Offset function not working with direct slicers

[AlexaderMilland]

I can't quite graps why this issue is happening.
Basically my offset function return blank values when im applying a slicer. 
It's only doing this when the slicer is directly part of the offset function, so i can easily apply a filter year or so. 
I understand if picked non-consecutive weeks, but I don't? 

Orders - Offset % =

CALCULATE([Orders],OFFSET(-1,ALLSELECTED('Calendar'[WeekName],'Calendar'[WeekKey]) ,OrderBy('Calendar'[WeekKey],ASC)))

[lbendlin]

Should work.  Can you post a sample pbix?