How long will it take for deleted leads to be reflected in database?

Hello,

I am a member of a team that inherited a very messy instance of Marketo. We recently went over our compliance limit are are trying to remove a large amount of leads that have no marketable value from Marketo.

We built a list of people that were in Marketo but not Salesforce. This list amounted to about 31,000 people due to poor database management from the people we inherited the system from. I then followed the steps from this support document: Delete People in a Smart List or List - Marketo Docs - Product Documentation. I built the list in Marketing Activities, selected all, and then finally clicked delete person. I waited almost an hour for the process to run since it was so many people, processed in batches of 200. When it was done, the smart list I had built was empty (besides a few unsubscribes) but when I went to the database tab, the "All People" system smart list still showed the same count as when we started. The people that were deleted were pulled directly from this list (and then compared to a list of everyone in Salesforce both leads and contacts) so this makes no sense to me.

I spot checked about 10 leads from the deleted list and searching by email I couldn't find any of them in the database.

I am confused by this all but I am sure there is a simple explanation. Anyone with experience deleting such a large number of people from a database, how long does it typically take for the deletion to be reflected in the database tab of Marketo? Is there anything I missed? I appreciate any response.