Loop block iteration failing on Data Action JSON array

Architect & Flows
1

Stuck on the Loop block syntax for parsing a JSON array from a custom Data Action. The Data Action returns a users array, but the Loop block throws a validation error when I try to set the iteration variable.

Here is the payload structure I am working with:

{
 "users": [
 { "id": "123", "name": "Alice" }
 ]
}

Error: Invalid expression. Cannot iterate over non-array type.

Is the path syntax data_action_response.users wrong, or do I need to cast the type explicitly in the Loop configuration?