"Failed to read data source" when creating authenticationContextClassReferences

I try to create a conditional access authentication context. I use the following code:

resource "msgraph_update_resource" "authctx_pim_role_activation" {
  url        = "identity/conditionalAccess/authenticationContextClassReferences/c2"
  api_version = "v1.0"
  body = {
    displayName = "Privileged Identity Management: Role Activation"
    description = "This context is used to apply conditional access policies to Privileged Identity Management (PIM) activations."
    isAvailable = true
  }

}

However, apply fails with this error:

Error: Failed to read data source
│ 
│   with module.conditional_access.msgraph_update_resource.authctx_pim_role_activation,
│   on conditional_access/main.tf line 64, in resource "msgraph_update_resource" "authctx_pim_role_activation":
│   64: resource "msgraph_update_resource" "authctx_pim_role_activation" {
│ 
│ GET
│ https://graph.microsoft.com/v1.0/identity/conditionalAccess/authenticationContextClassReferences/c2
│ --------------------------------------------------------------------------------
│ RESPONSE 201: 201 Created
│ ERROR CODE UNAVAILABLE
│ --------------------------------------------------------------------------------
│ {
│   "@odata.context": "[https://graph.microsoft.com/v1.0/$metadata#identity/conditionalAccess/authenticationContextClassReferences/$entity",](https://graph.microsoft.com/v1.0/$metadata#identity/conditionalAccess/authenticationContextClassReferences/$entity%22,)
│   "id": "c2",
│   "displayName": "Privileged Identity Management: Role Activation",
│   "description": "This context is used to apply conditional access policies to Privileged Identity Management (PIM) activations.",
│   "isAvailable": true
│ }

The authentication context was created successfully even though terraform reports an error.

Start with the msgraph_update_resource resource and reproduce the configuration in conditional_access/main.tf at line 64 against the authenticationContextClassReferences/c2 endpoint. Trace the post-create read that reports the 201 response as a failure; done means Terraform apply completes without a false error while the authentication context remains created.