ACTIVITY FEED do not show all the pre-identify event after ID_merge.

ACTIVITY FEED do not show all the pre-identify event after distinct_id and our account_id were already merged.
 

we implement it depending on https://help.mixpanel.com/hc/en-us/articles/115004497803-Identity-Management-Best-Practices

• sign-up: call alias from server-side
• login: call identify from client-side
• logout or sign-out: call reset from client-side

I figured out pre-identify events on the EVENT board are merged into one distinct_id (in the case, our account_id)  after calling identify, which is the right way.

When I clicked distinct_id, however, pre-identify events do not show on the ACTIVITY FEED.

(EVENT link: https://mixpanel.com/project/2607813/view/3141199/app/events#~(dateRange~(type~'in*20the*20last~window~[…]faultType~'string))~showQueryBuilder~true))
(ACTIVITY FEED link: https://mixpanel.com/project/2607813/view/3141199/app/profile#distinct_id=436173343685536&~(dateRange~([…]0the*20last~window~(value~30~unit~'week))))

I didnt find any failure_reason for each event and it didnt update yet though 12 hours went by which seems to happen frequently.
Can you guess what's the reason for this situation ?
Thanks :)