Create class notebook fails if group contains disabled users, even if teacher, student sections of create call is empty - onenote-api

Question

Here is the scenario to reproduce the error:
Take a Microsoft Education Tenant (Demo Tenant is sufficient)
Create a fresh user with valid office 365 license and usage location
Disable the account (set block sign-in) to true in Azure Portal
Create a group and add this user as member
That's the minimum scenario we need. It is also possible to have other (enabled) users within the group, but that doesn't change the behaviour. Now let's follow the documentation to create a class notebook:
POST https://www.onenote.com/api/v1.0/myOrganization/groups/{groupId}/notes/classNotebooks/?omkt=de-de
{
"name": "Class notebook of my group",
"teachers": [],
"students": [],
"studentSections": [],
"hasTeacherOnlySectionGroup": true
}
So, the unified group has just one member with an disabled account, but this specific user is NOT added into the teachers or students section of the create request. Nevertheless the following error message occurs:
System.Net.Http.HttpRequestException: Response status code does not indicate success: 404 (NotFound).
{
"error": {
"code": "30109",
"message": "The following users are invalid: Message: Der angegebene Benutzer disabled.user#mydomain.com wurde nicht gefunden., ServerErrorCode: -2146232832, ServerErrorTypeName: Microsoft.SharePoint.SPException",
"#api.url": "https://aka.ms/onenote-errors#C30109"
}
}

Answer 1

After getting the clarification from Marc our current procedure is as follows:
Get a list of all disabled users.
Enable all of them.
Wait one minute (cause Graph needs some time to propagate this).
Create the course notebook through OneNote API.
Disable all users from the initial list again.
With this everything works as expected.

Answer 2

The error message isn't clear but Teachers maps Owners and Students maps to Members. So even though you didn't specify this user in the students collection, they are a member of the Group and therefore they're considered part of the students collection.
When an 30109 error like this is encountered, the only workaround is either iterate through the Owners and Members and remove any disabled accounts, or parse the message property for the UPN (disabled.user#mydomain.com). It is less than ideal I know.