## Bug description

When I create a fairly simple query (event + 1 filter) and click on the graph to open the person models (sep 3), I get 25 people, whereas the graph says there should be 17 ([see this internal link](https://app.posthog.com/insights?insight=TRENDS&interval=day&display=ActionsLineGraph&events=%5B%7B%22id%22%3A%22insight%20loaded%22%2C%22name%22%3A%22insight%20loaded%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%2C%22math%22%3A%22dau%22%7D%5D&filter_test_accounts=true&actions=%5B%5D&new_entity=%5B%5D&breakdown=false&breakdown_type&properties=%5B%7B%22key%22%3A%22insight%22%2C%22value%22%3A%5B%22STICKINESS%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D&date_from=2021-08-30&date_to=2021-09-06#personModal=%7B%22action%22%3A%7B%22id%22%3A%22insight%20loaded%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%2C%22name%22%3A%22insight%20loaded%22%2C%22math%22%3A%22dau%22%2C%22math_property%22%3Anull%2C%22properties%22%3A%5B%5D%7D%2C%22label%22%3A%22insight%20loaded%22%2C%22date_from%22%3A%222021-09-03%22%2C%22date_to%22%3A%222021-09-03%22%2C%22filters%22%3A%7B%22insight%22%3A%22TRENDS%22%2C%22interval%22%3A%22day%22%2C%22display%22%3A%22ActionsLineGraph%22%2C%22events%22%3A%5B%7B%22id%22%3A%22insight%20loaded%22%2C%22name%22%3A%22insight%20loaded%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%2C%22math%22%3A%22dau%22%7D%5D%2C%22filter_test_accounts%22%3Atrue%2C%22actions%22%3A%5B%5D%2C%22new_entity%22%3A%5B%5D%2C%22breakdown%22%3Afalse%2C%22breakdown_type%22%3Anull%2C%22properties%22%3A%5B%7B%22key%22%3A%22insight%22%2C%22value%22%3A%5B%22STICKINESS%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%2C%22date_from%22%3A%222021-08-30%22%2C%22date_to%22%3A%222021-09-06%22%7D%2C%22saveOriginal%22%3Atrue%7D))

The same thing happens with a [breakdown query](https://app.posthog.com/insights?insight=TRENDS&interval=day&display=ActionsLineGraph&events=%5B%7B%22id%22%3A%22insight%20loaded%22%2C%22name%22%3A%22insight%20loaded%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%2C%22math%22%3A%22dau%22%7D%5D&filter_test_accounts=true&properties=%5B%5D&actions=%5B%5D&new_entity=%5B%5D&breakdown=insight&breakdown_type=event)

## Expected behavior

The person modal should have 17 people

## How to reproduce

1. Go to link above
2. Click on sep 3
3. Verify there are 25 people

## Environment

- [ ] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_

## Additional context

Looks like when passing through the date as 3rd of september, the query looks like this, which is probably where the 25 comes from (3rd + 4th of sept combined):
![image](https://user-images.githubusercontent.com/1727427/132249205-22c77f31-aee8-4d6a-819f-eafecd02ad46.png)


cc @EDsCODE @macobo 


#### *Thank you* for your bug report – we love squashing them!

posthog/api/test/test_action_people.py
import json
from freezegun import freeze_time
from posthog.constants import ENTITY_ID, ENTITY_MATH, ENTITY_TYPE, TRENDS_CUMULATIVE
from posthog.models import Action, ActionStep, Cohort, Event, Organization, Person
from posthog.queries.abstract_test.test_interval import AbstractIntervalTest
from posthog.tasks.calculate_action import calculate_actions_from_last_calculation
from posthog.test.base import APIBaseTest
def action_people_test_factory(event_factory, person_factory, action_factory, cohort_factory):
    class TestActionPeople(AbstractIntervalTest, APIBaseTest):
        def _create_events(self, use_time=False):
            action_factory(team=self.team, name="no events")
            sign_up_action = action_factory(team=self.team, name="sign up")
            person = person_factory(team_id=self.team.pk, distinct_ids=["blabla", "anonymous_id"])
            secondTeam = Organization.objects.bootstrap(None, team_fields={"api_token": "token456"})[2]
            freeze_without_time = ["2019-12-24", "2020-01-01", "2020-01-02"]
            freeze_with_time = [
                "2019-12-24 03:45:34",
                "2020-01-01 00:06:34",
                "2020-01-02 16:34:34",
            ]