There are hundreds of duplicates of events being sent by the app.
Here's the query I used to catch the problem in my meeting with @Dbrant:
```
WITH top_device AS (
SELECT
CONCAT(year, '-', LPAD(month, 2, '0'), '-', LPAD(day, 2, '0')) AS date,
useragent.wmf_app_version AS app_version,
event.app_install_id AS install_id,
SUM(event.totalPages) AS total_pages,
SUM(event.length) AS total_time,
COUNT(1) AS n_sessions
FROM event.MobileWikiAppSessions
WHERE revision = 18115099
AND year = ${year} AND month = ${month} AND day = ${day} AND hour = ${hour}
AND useragent.os_family = 'Android'
AND useragent.wmf_app_version > '2.7.2'
AND useragent.wmf_app_version != 'r'
AND NOT useragent.is_bot
GROUP BY
CONCAT(year, '-', LPAD(month, 2, '0'), '-', LPAD(day, 2, '0')),
useragent.wmf_app_version, event.app_install_id
ORDER BY n_sessions DESC
LIMIT 1
)
SELECT event
FROM top_device
LEFT JOIN event.MobileWikiAppSessions AS sessions ON (
sessions.event.app_install_id = top_device.install_id
AND sessions.revision = 18115099
AND sessions.year = ${year} AND sessions.month = ${month} AND sessions.day = ${day} AND sessions.hour = ${hour}
)
ORDER BY event.client_dt ASC
LIMIT 1000000;
```
The `client_dt` on these shows that the events are generated & sent by the app ~10s apart. So on our side when we count # of sessions by counting events, we're seeing 800+ "sessions" from some users //per day//.