Before 4.2 version, the LLD rule did require an array:

{"data":[ { .. } , { .. } ]

Starting with 4.2 and newer, it's acceptable:

{ { .. } , { .. } ]

The error message when JSON consistency is not good still highlights the necessity of "data":

Cannot find the "data" array in the received JSON object

For new users, it's confusing to ask for extra structure as it's not mandatory anymore.