Graph Search API returns all sites despite "Sites.Selected" App-Only permission

Context:

I am using an Azure AD App Registration with the Sites.Selected application permission. My goal is to limit the application's access to specific SharePoint sites only.

Configuration:

I assigned the Sites.Selected permission to the app (App ID: [App-ID]).

I successfully granted write (FullControl) access to specific sites using the Permissions endpoint.

Request to grant permission:

POST https://graph.microsoft.com/v1.0/sites/[Site-ID]/permissions
{
  "roles": ["fullcontrol"],
  "grantedToIdentities": [
    {
      "application": {
        "id": "[App-ID]",
        "displayName": "test-site.selected-permission"
      }
    }
  ]
}

Testing Standard Endpoints (Working as expected):

When I call GET https://graph.microsoft.com/v1.0/sites, I get an empty value list, or only the specific site, which is expected behavior for Sites.Selected.

{
    "@odata.context": "https://graph.microsoft.com/v1.0/$metadata#sites",
    "value": []
}

When I try to access users via /users, I get Authorization_RequestDenied, which is also expected.

The Issue (Search API):

When I use the Search API, the application returns all sites in the tenant, ignoring the Sites.Selected restriction.

Request:

POST https://graph.microsoft.com/v1.0/search/query 
Content-Type: application/json

{
    "requests": [
        {
            "entityTypes": [ "site" ],
            "query": {
                "queryString": "(contentclass:STS_Site OR contentclass:STS_Web)"
            },
            "region": "US" 
        }
    ]
}

Response (Unexpected):

It returns a total of ~1300 results, including sites I have not explicitly granted access to.

{
    "value": [
        {
            "hitsContainers": [
                {
                    "hits": [
                        {
                            "hitId": "[Site-ID-1]",
                            "resource": {
                                "displayName": "Policy_FE_Automation_Site",
                                "webUrl": "https://[Tenant].sharepoint.com/sites/Policy_FE_Automation_Site"
                            }
                        },
                        {
                            "hitId": "[Site-ID-2]",
                            "resource": {
                                "displayName": "Restricted_Site_Example",
                                "webUrl": "https://[Tenant].sharepoint.com/sites/Restricted_Site_Example"
                            }
                        }
                        // ... returns 1349 results
                    ],
                    "total": 1349,
                    "moreResultsAvailable": true
                }
            ]
        }
    ]
}

Token Analysis:

I inspected my Access Token. I noticed a wids (Workload ID) claim, but I have not assigned any Directory Roles (like SharePoint Admin) to this application manually, only the API Permission Sites.Selected.

Decoded Token (Relevant parts):

{
  "aud": "https://graph.microsoft.com",
  "roles": [
    "Sites.Selected"
  ],
  "wids": [
    "0997a1d0-0d1d-4acb-b408-d5ca73121e90" 
  ],
  "idtyp": "app"
}

Questions:

Is it expected behavior that the Microsoft Graph Search API (/search/query) bypasses Sites.Selected restrictions and exposes the existence of all sites?

Does Sites.Selected only apply to direct GET requests (e.g., /sites/{id}) and not the Search index?

Could the wids claim 0997a1d0-0d1d-4acb-b408-d5ca73121e90 be overriding the permission scope? If so, where does this come from if I haven't assigned a Directory Role?

Any guidance on how to restrict Search results to only the sites defined in Sites.Selected would be appreciated.