## Bug description

We have an issue in which the table of users for each cohort does not contain the same number of users as the table reports.

### Example
([Source](https://app.posthog.com/insights?startEntity=%7B%22actions%22%3A%5B%5D%2C%22events%22%3A%5B%7B%22id%22%3A%22user%20signed%20up%22%2C%22type%22%3A%22events%22%2C%22order%22%3A0%2C%22name%22%3A%22user%20signed%20up%22%7D%5D%2C%22new_entity%22%3A%5B%5D%7D&returningEntity=%7B%22events%22%3A%5B%7B%22id%22%3A%22%24pageview%22%2C%22name%22%3A%22%24pageview%22%2C%22type%22%3A%22events%22%7D%5D%7D&retentionType=retention_first_time&date_to=2020-04-05T12%3A59%3A36.001Z&period=w&display=ActionsTable&properties=%5B%7B%22key%22%3A%22id%22%2C%22value%22%3A71%2C%22type%22%3A%22cohort%22%7D%2C%7B%22key%22%3A%22%24current_url%22%2C%22value%22%3A%22www.posthog.com%22%2C%22operator%22%3A%22not_icontains%22%2C%22type%22%3A%22event%22%7D%2C%7B%22key%22%3A%22%24current_url%22%2C%22value%22%3A%22https%3A%2F%2Fposthog.com%22%2C%22operator%22%3A%22not_icontains%22%2C%22type%22%3A%22event%22%7D%2C%7B%22key%22%3A%22%24current_url%22%2C%22value%22%3A%22localhost%22%2C%22operator%22%3A%22not_icontains%22%2C%22type%22%3A%22event%22%7D%2C%7B%22key%22%3A%22%24current_url%22%2C%22value%22%3A%22127.0.0.1%22%2C%22operator%22%3A%22not_icontains%22%2C%22type%22%3A%22event%22%7D%2C%7B%22key%22%3A%22%24current_url%22%2C%22value%22%3A%220.0.0.1%22%2C%22operator%22%3A%22not_icontains%22%2C%22type%22%3A%22event%22%7D%5D&insight=RETENTION))

**Table shows 6 users in cohort:**
<img width="222" alt="" src="https://user-images.githubusercontent.com/5864173/102359528-867d9500-3f76-11eb-8134-50d0adcbd5b8.png">

**Persons list shows a lot more than 6 users in cohort:**
<img width="150" alt="" src="https://user-images.githubusercontent.com/5864173/102359599-9a28fb80-3f76-11eb-9cb8-61b37ddd4d95.png">


## Expected behavior
The persons list and the retention table should match.


## How to reproduce

See description above.

## Environment

Cloud, Clickhouse.

## Additional context

Currently blocking internal personas analysis.

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

ee/clickhouse/queries/clickhouse_retention.py
def _execute_sql(self, filter: RetentionFilter, team: Team,) -> Dict[Tuple[int, int], Dict[str, Any]]:
        period = filter.period
        prop_filters, prop_filter_params = parse_prop_clauses(filter.properties, team.pk)
        target_entity = filter.target_entity
        returning_entity = filter.returning_entity
        is_first_time_retention = filter.retention_type == RETENTION_FIRST_TIME
        date_from = filter.date_from
        date_to = filter.date_to
        target_query = ""
        target_params: Dict = {}
        trunc_func = get_trunc_func_ch(period)
        target_query, target_params = self._get_condition(target_entity, table="e")
        returning_query, returning_params = self._get_condition(returning_entity, table="e", prepend="returning")
        target_query_formatted = "AND {target_query}".format(target_query=target_query)
        returning_query_formatted = "AND {returning_query}".format(returning_query=returning_query)
        reference_event_sql = (REFERENCE_EVENT_UNIQUE_SQL if is_first_time_retention else REFERENCE_EVENT_SQL).format(
            target_query=target_query_formatted, filters=prop_filters, trunc_func=trunc_func,
        )
        target_condition, _ = self._get_condition(target_entity, table="reference_event")
        if is_first_time_retention:
            target_condition = target_condition.replace("reference_event.uuid", "reference_event.min_uuid")
            target_condition = target_condition.replace("reference_event.event", "reference_event.min_event")
        returning_condition, _ = self._get_condition(returning_entity, table="event", prepend="returning")