At data load/refresh time

Only when explicitly requested, however, this wording confuses row context, filter context, or evaluation timing and therefore misses the exact DAX behavior being tested.

Never - they are static values, although it sounds technically credible, it does not align with how DAX functions propagate context in this scenario.

A syntax-level statement that appears valid but actually describes iterator usage in a context where scalar evaluation is required

At runtime when viewing the report, although it sounds technically credible, it does not align with how DAX functions propagate context in this scenario.