angular - Custom claims in msal.js access token

Question

I have secured my Angular 7 application by using msal.js. I've created a custom policy that returns custom claimtypes in the id_token and in the access_token. To achieve this, I've been following this tutorial: https://docs.microsoft.com/en-us/azure/active-directory-b2c/active-directory-b2c-custom-rest-api-netfw. When I use the acquireTokenSilent() msal.js method, the JWT token does not contain the custom claims (contract, fileUploadAllowed).

When I use the "Run Now" button on the Custom Policy pane in Azure, I do receive an access_token that has the custom claims.

The payload of the JWT token thats is generated by running the policy in Azure (Changed some of the values):

{
  "iss": "https://login.microsoftonline.com/guid/v2.0/",
  "exp": 1548416392,
  "nbf": 1548455092,
  "aud": "c152h904-835a-496f-8919-e74f5013374c",
  "contract": "Contract03",
  "fileUploadAllowed": false,
  "sub": "25a6ec11-16fd-477a-8917-e0728c69e1db",
  "nonce": "defaultNonce",
  "scp": "portal.read user_impersonation",
  "azp": "c154c904-835a-496f-8919-e74f5087384c",
  "ver": "1.0",
  "iat": 1542213053
}

The payload of the JWT token (access_token) that is generated by msal.js:

{
  "iss": "https://login.microsoftonline.com/guid/v2.0/",
  "exp": 1548416396,
  "nbf": 1548455092,
  "aud": "c152h904-835a-496f-8919-e74f5013374c",
  "sub": "25a6ec11-16fd-477a-8917-e0728c69e1db",
  "nonce": "e6df86c9-7c19-4cb5-a4ac-1aa2a89b1951",
  "scp": "portal.read user_impersonation",
  "azp": "c154c904-835a-496f-8919-e74f5087384c",
  "ver": "1.0",
  "iat": 1542213953
}

I want to receive the custom claims in the access_token that is generated by msal.js. Does anyone know what I should do in order to make this work?

Thank you.