How to manage weekly grouping start points?

Hi, i have a question about weekly grouping.

Today (2020-07-08) i have this graph:


from this query:

or

SELECT
  $__timeGroupAlias(created_at,$__interval,0),
  count(id) AS "Médicos"
FROM app_doctor
WHERE
  $__timeFilter(created_at)
GROUP BY 1
ORDER BY $__timeGroup(created_at,$__interval,0)

The question: why i have a point starting into 07/02 and not in 07/08?

Thanks.

Does anyone know anything about it?