Different Number of Contacts Appear

Description of the issue: When popping out Contacts from an account, the number of contacts displayed changes despite using the same view and parameters
Account name: GWU
Region: US
Client version: 25.2
Steps to reproduce:

1. Login as usiadmin/ITRocks2014 https://supportwebus.ungerboeck.com/GWU_Prod/
2. Go to Accounts - All from the Main Menu
3. Search for account code 00033298 and edit the account and go to the Contacts tab.
4. See that on the Contacts tab, over 15,000 contacts appear.

5. Now click on the icon in the Contacts grid to open up the grid in a new tab.
6. See that only 3 contacts now appear.

7. The view is the same in both places, Active Contacts, with the same parameters.
8. Cathy and I took a look and could not figure out why the number of contacts visible is different despite it using the same search parameters.

Observed results vs Expected results: Only 3 contacts appear when you open the tab in a new window. All 15,000+ should appear.

What is the job the client is trying to accomplish: View all contacts related to an account.
Business impact if not resolved: Confusing and potentially inaccurate for end-users.
Links to articles where you've looked for solutions and also other steps you've taken to research the issue: Tried clearing filters and applying different views and cannot get more than 3 accounts to load on the popped out window. Also verified the account classes on the accounts. We can't see any reason why just the 3 are displaying.
Link to Zendesk ticket: https://ungerboeck.zendesk.com/agent/tickets/367878
Local v30 URL: https://supportwebus.ungerboeck.com/GWU_Prod/

Recording: https://app.birdie.so/library/ad1e7c57-6101-49c9-b770-7b9b5c10d7dc