Steps to reproduce:
(clean Ibexa DXP 4.x)

• Add Folder 'Foo Campaign' below root Landing Page
• Add Folders Images-Foo and Images-Foo-Bar below 'Media'
• Create one Image Content Item below /Media/Images-Foo (Name Should be 'Test')
• Create one Image Content Item below /Media/Images-Foo-Bar (Name Should be 'Test')

Add yaml config:

ibexa:
    siteaccess:
        list: [foo-campaign]
        groups:
            site_group: [foo-campaign]
        match:
            Map\URI:
                foo: foo-campaign
    system:
        foo-campaign:
            content:
                tree_root:
                    # LocationId of "Foo Campaign"
                    location_id: 68
                    excluded_uri_prefixes: [ /media/images-foo/ ]

Open URLS:
https://[host]/foo/media/images-foo/test
https://[host]/foo/media/images-foo-bar/test

Result:
Both URLs are resolved and Content Items are shown

Expected:
Second URL should not be resolved in foo-campaign Site Acccess as /media/images-foo-bar/ is not in excluded_uri_prefixes