Hello,
I have used SamePeriodLastYear successfully in power pivot table in Excel and it worked like magic.
I tried to implement the same formula to the same source through Power BI desktop and it works up to the point when I'm starting to slice the result by anything (category for example; which again, worked in Pivot Table).
I tried (probably) every workaround available on the Internet (from dateadd, through hasonevalue to custom filtering) and now goes my set of questions: Is this a normal behaviour for Power BI Desktop? Is PBI as limited in comparison with Excel? Maybe someone knows if this is a know issue and Microsoft is working on it?