In my Mixpanel project, the Merge ID setting shows: "This project does not have ID Merge enabled."
This means my project is using the Legacy ID Management system. However, in the data, I see that some distinct_id values have a $device: prefix.
Can you explain what this means under the Legacy ID Management?
Also, I thought that in Legacy ID Management, the distinct_id does not change until the user logs out.
But in my data, I see a single distinct_id associated with more than two different user_ids.
Can you help explain why this happens?