CXone Architect Loop block not iterating over Data Action JSON array

The Loop block in Architect skips execution when fed a JSON array from a REST Data Action. The payload is [{"id": 1, "name": "test"}] and the loop variable is set to data.response.body, but the iteration count stays at zero. No error is thrown, just silence. Is the schema definition for the loop item wrong or is this a known platform bug with array parsing?