Blueprint SheetSummary Formulas

In the Blueprint project plan, there are Sheet Summary formulas, providing the 'Category' & 'Initiative' from the Project Metadata sheet. See below:

=({Project Metadata | Category})

=({Project Metadata | Initiative})

I need to add a new SheetSummary formula in the blueprint project plan to pull in the 'Workstream' from the Project Metasheet. The formula below is not working:

=({Project Metadata | Workstream})

Any advice?

Answers