Files created from app using Graph API always shown as created by "Sharepoint App"

My app is creating a file (DriveItem) using Graph API. It's using GraphServiceClient from Microsoft.Graph nuget and gets access token with ClientSecretCredential.

Here's the part when the file gets created:

public async Task CreateFile(string driveId, string folderId, string filename, byte[] content)
{
    var driveItem = new DriveItem()
    {
        Name = filename,
        File = new Microsoft.Graph.File()
        {
            MimeType = "application/pdf"
        },
        AdditionalData = new Dictionary<string, object>()
        {
            { "@microsoft.graph.conflictBehavior", "rename" }
        }
    };

    var response = await _client.Drives[driveId].Items[folderId].Children.Request().AddAsync(driveItem);
    await _client.Drives[driveId].Items[response.Id].Content.Request().PutAsync<DriveItem>(new MemoryStream(content));
}

The problem is that the file that's created has the following createdBy identity set:

"createdBy": {
    "application": {
        "id": "[app-id]",
        "displayName": "[app-display-name]"
    },
    "user": {
        "displayName": "SharePoint App"
    }
}

and the name shown in CreatedBy column when viewing files list in Teams is "SharePoint App" instead of my app's display name. When I try to manually set values for CreatedBy property and overwrite user's displayName it simply get ignored.

Am I missing something or is this by design and files created by apps ale always shown as created by "SharePoint App"?