The Mixpanel dashboard shows a different Distinct ID than what I passed in .identify() function

[brunohenriquesk1]

Our app uses the identify() method right after user login, passing the MongoDB user ID as the identifier. Most of the time, this works as expected. However, sometimes I observe the following behavior:

• The identify event appears in the Mixpanel dashboard, but it assigns the previous random distinct_id (generated before the user logged in) instead of the MongoDB user ID.

• This issue occurs more frequently when switching accounts after calling reset() and then calling identify() again after the new user logs in.

When I check the distinctId locally using Mixpanel.mainInstance().distinctId it correctly shows the MongoDB user ID.

Here is it working as expected when I switch to another user

SDK Version: v4.3.1 (latest)

// On login
Mixpanel.mainInstance().identify(distinctId: mongoUserId)

//Check if user id is correct 
Mixpanel.mainInstance().distinctId

// On logout
Mixpanel.mainInstance().reset()

It's pretty much the same issue as this one but on iOS

mixpanel/mixpanel-react-native#207

[santigracia]

Hi Bruno, Santi here from Mixpanel.

First of all, thank you for raising this issue.

Assuming your project is using Identity Merge (You can check in Project Settings>Id Merge), the behavior you're seeing is expected and is related to Mixpanel's identity cluster and canonical ID selection logic. Your implementation is correct, as long as you're calling identify() and reset() at the right times and setting your MongoDB user ID as a user property.

The Mixpanel UI doesn't always show the user ID you pass to identify(). This is because Mixpanel automatically chooses an ID (either the device ID or the user ID) to be the canonical distinct_id. This selection isn't user-configurable. So, even after you call identify(), the dashboard might temporarily show the previous device ID.

This temporary mismatch is due to a propagation delay that can take up to 24 hours for the ID merge to fully resolve across Mixpanel's systems (normally happens in ~4 hours and I noticed your screenshot is showing 2 hours ago). While the Activity Feed updates in nearly real-time, other reports and queries might show temporary inconsistencies that will eventually resolve.

Recommendation: Continue to call identify() immediately after login and reset() on logout. This is the recommended approach.

Sources: https://docs.mixpanel.com/docs/tracking-methods/id-management/identifying-users-original#faq

Thank you for bringing this issue to our attention. Please, if this issue is still happening after 24 hours, would you mind raising a ticket with our Support team at support@mixpanel.com ? we would be able to investigate further looking directly at the data.