After a dance with Salesforce support they confirmed that in Salesforce there is no single document stating what is needed for that but here it is:
Sales Cloud Standard User License, Sys Admin not needed
Read Access to Leads, View All is not required
Log in to Subscriber Organization system permission (a permission set is enough for that)
The code above doesn't specify a publication list at all, so it is unsubbing at the child BU level and flowing down to the publist automatically.
This example will work (but will not log an unsub event).
SET @ll_sub = CreateObject("Subscriber")
The behavior you are describing seem specific to the one that happens after a contact has been deleted using the Contact Delete process.
If you recently deleted some contacts, they are now in the Suppression period - the default length is 14 days, but it's possible that you used a different period.
In that timeframe, contacts won't be visible in the UI, ...
Tracking data is stored in Data Views, each BU has it’s own set of Data Views.
To achieve your goal, you wold have to create a Shared Data Extension and create an automation in each BU separately, to query Data Views and update that Shared Data Extension. Then, create a separate automation in Parent BU, with a query logic to pull relevang subscribers from ...