Teams - GET filesFolder API issue

Question

Hello.

We have a new problem when run this request: https://learn.microsoft.com/en-us/graph/api/channel-get-filesfolder?view=graph-rest-1.0&tabs=http

That is, GET /teams/{id}/channels/{id}/filesFolder

Previously, if a Team Channel was created via the API, it wasn't linked to a folder with files, until a user clicks Files in a Teams client and thus initializes it. And until it was initialized, the request would return Not Found 404.

However, since around February 25, 2021, in case the authenication uses MFA, we now get this error: Value cannot be null. Parameter name: token. But, the Authorization Token is present in the request as we verified with a traffic capture. Once you initialize the folder by clicking Files, the request starts to return valid data.

Is this a bug? Thanks.

GET https://graph.microsoft.com/v1.0/teams/.../channels/.../filesFolder?$select=id,name,webUrl,parentReference HTTP/1.1  
Content-Type: application/json  
User-Agent: <...>  
Authorization: Bearer ...  
Host: graph.microsoft.com  
Connection: Keep-Alive  
  
HTTP/1.1 400 Bad Request  
Cache-Control: private  
Content-Type: application/json  
request-id: ...  
client-request-id: ...  
x-ms-ags-diagnostic: {"ServerInfo":{"DataCenter":"West Europe","Slice":"SliceC","Ring":"5","ScaleUnit":"005","RoleInstance":"AGSFE_IN_67"}}  
Strict-Transport-Security: max-age=31536000  
Date: Mon, 01 Mar 2021 19:38:40 GMT  
Content-Length: 310  
  
{  
  "error": {  
    "code": "BadRequest",  
    "message": "Value cannot be null.\r\nParameter name: token",  
    "innerError": {  
      "date": "2021-03-01T19:38:41",  
      "request-id": "...",  
      "client-request-id": "..."  
    }  
  }  
}