Facebook API: Page access token is missing scopes - facebook-graph-api

Question

After retrieving a page access token using a user access token, some scopes are missing.
I use the user access token with these details:
"app_id": "123",
"type": "USER",
"application": "lorem",
...
"scopes": [
"pages_show_list",
"pages_messaging",
"pages_messaging_subscriptions",
"pages_manage_metadata",
"public_profile"
],
Then I request the page access token from endpoint:
https://graph.facebook.com/me/accounts
I receive a page access token:
"app_id": "412378670482",
"type": "PAGE",
"application": "lorem",
...
"profile_id": "123",
"scopes": [
"pages_show_list",
"public_profile"
],
Can anybody explain why the scope has been reduced?
The user that created the USER token has "full page" access to the page.
EDIT Full page token debug:
The most remarkable thing is here, that the profile_id is not listed in the granular scopes of e.g. "pages_manage_metadata". So the reduced scope reflects the missing ids.
"app_id": "3926422237",
"type": "PAGE",
"application": "lorem",
"data_access_expires_at": 1639517367,
"expires_at": 0,
"is_valid": true,
"issued_at": 1603451677,
"profile_id": "1023865413",
"scopes": [
"pages_show_list",
"public_profile"
],
"granular_scopes": [
{
"scope": "pages_show_list"
},
{
"scope": "pages_messaging",
"target_ids": [
"2053841064733",
...
]
},
{
"scope": "pages_messaging_subscriptions",
"target_ids": [
"2053841064733",
...
]
},
{
"scope": "pages_manage_metadata",
"target_ids": [
"2053841064733",
...
]
}
],
"user_id": "16954674",
"expires_at_dt": "1970-01-01",
"data_access_expires_at_dt": "2021-12-14"
}