Why is my S3 folder named like a date?

The dated-looking folder (for example 2022-03-16/) in your cloud-storage destination is the API version prefix, not a data date.

The dated-looking folder (for example 2022-03-16/) in your cloud-storage destination is the API version prefix, not a data date.

It is a global setting and stays constant as the top-level object prefix for every payload written, so all new objects land under it regardless of when they arrive.

Folder names below it map to event types (activity, sleep, daily, auth_success, deauth, large_request_processing, etc.), and filenames carry the actual event start_time.

This is expected behaviour. See cloud storage destinations.