Hi @ChrisF ,
You can change the measure formatting using Format() function:
--annotations.group=Predicted by issues
Case when
DateInPeriod(
[Measures].[Project predicted date],
[Time].CurrentHierarchyMember)
Then
'Project Predicted date - '
|| Format([Measures].[Project predicted date], '"W"ww, yyyy')
End
See more examples in this community post (at the end):