populatedBy directive does not work together with the private directive

[AccsoSG]

Is your feature request related to a problem? Please describe.
I would like to calculate a field with populatedBy. So on every create or update a corresponding callback function should calculate the field.

However, this field should not be retrievable via the API, but only used for internal purposes. I tried to implement this with the private directive. However, when using the private directive, the callback function is no longer executed. So no value is stored in the database for the field.

interface INode {
  transactionId: String @populatedBy(operations: [CREATE, UPDATE], callback: "transactionId") @private
}

type Person implements INode {
  transactionId: String
  name: String
}