There are two calculation items in the Sales Doubler calc group, one is SELECTEDMEASURE() and the other is SELECTEDMEASURE() * 2.
The calculation group is not applied in this mode. It just exists. If I change the Sales Doubler item to just SELECTEDMEASURE() as well, the smart narrative works, but if it is anything except SELECTEDMEASURE() it returns blank, even though the card works.
I know that by applying the CG will cause an error because you cannot multiply text * 2, but that isn't the issue. I can control that with ISSELECTEDMEASURE() or by using the CG in a slicer then editing the interactions to exclude the card and Smart Narrative, but I cannot even get that far. Doing that does not restore the smart narrative.
This seems to be a relatively new issue. I do not recall seeing this in the past few months, and I make extensive use of measures in Smart Narratives to return the text I want.