You browse through your tenants and click to select one of them (Customer1).
Then you use search to look for another tenant and select it (Customer2).
Now you switch to the Users tab and see the list of users belonging to the previous tenant (Customer1), not the latest one you have selected.
Issue in the product.
This issue has been fixed in Acronis Cyber Protect 9.0 Update 2.
As a workaround for older versions, please select the tenant in the Clients tab and then navigate to the Users tab.