File upload fails with ODataError: Invalid request

Describe the bug

I have a simple app to upload files form a specific folder to a specific OneDrive folder. This app has been working without issues for over 18 months. Since mid-February, it stopped working with this error:

Invalid Request.

Here my code snippet:

public static async Task SyncFileOld(string driveId, SyncItem syncItem)
     {
         try
         {
             // https://learn.microsoft.com/en-us/graph/sdks/large-file-upload?tabs=csharp
             var driveUpload = new DriveUpload.CreateUploadSessionPostRequestBody()
             {
                 Item = new DriveItemUploadableProperties
                 {
                     Name = Path.GetFileName(syncItem.Path),
                     AdditionalData = new Dictionary<string, object>
                     {
                         { "@microsoft.graph.conflictBehavior", "replace" },
                     },
                     FileSystemInfo = new Microsoft.Graph.Models.FileSystemInfo()
                     {
                         LastModifiedDateTime = File.GetLastWriteTimeUtc(syncItem.Path)
                     },
                     Description = "desc"
                 }
             };

             // note: this does not always return the correct info
             var response = await _graphServiceClient!
                 .Drives[driveId]
                 .Items[syncItem.FolderId]
                 .SearchWithQ(q: driveUpload.Item.Name)
                 .GetAsSearchWithQGetResponseAsync();

             if (response?.Value?.Count > 0)
             {
                 logger.Warn($"File {driveUpload.Item.Name} already exists. Skipping.");
                 return;
             }

             
// ==> this line throws the exception
var uploadSession = await _graphServiceClient!
                 .Drives[driveId]
                 .Items[syncItem.FolderId]
                 .ItemWithPath(driveUpload.Item.Name)
                 .CreateUploadSession
                 .PostAsync(driveUpload);


             logger.Trace($"Uploading {Path.GetFileName(syncItem.Path)} ...");

             using (var fileStream = File.OpenRead(syncItem.Path))
             {
                 int maxSliceSize = 320 * 1024 * 10;
                 var fileUploadTask = new LargeFileUploadTask<DriveItem>(
                     uploadSession, fileStream, maxSliceSize, _graphServiceClient.RequestAdapter);

                 var totalLength = fileStream.Length;
                 // Create a callback that is invoked after each slice is uploaded
                 IProgress<long> progress = new Progress<long>(prog =>
                 {
                     logger.Trace($"Uploaded {prog} bytes of {totalLength} bytes.");
                 });

                 var uploadResult = await fileUploadTask.UploadAsync(progress);

                 if (uploadResult.UploadSucceeded)
                 {
                     logger.Trace($"Uploaded {Path.GetFileName(syncItem.Path)} successfully.");
                 }
                 else
                 {
                     logger.Error($"Error in uploading {Path.GetFileName(syncItem.Path)}.");
                 }
             }

         }
         catch (Exception ex)
         {
             logger.Error(ex, $"Unable to upload file {syncItem.Path}.");
         }
     }

Variations: If I remove AdditionalData, I get a different error: 401 (access denied? not sure why). Nothing has changed in the app registration/permissions. I created a new app registration and still got the same error.

Expected behavior

The upload should work as expected.

How to reproduce

• Use the sample code from https://learn.microsoft.com/en-us/graph/sdks/large-file-upload?tabs=csharp and create a simple program that uploads any file.

SDK Version

5.73.0

Latest version known to work for scenario above?

No response

Known Workarounds

None, to my knowledge.

Debug output

</details>


### Configuration

- OS: Windows (11)
- .NET core 9.0

### Other information

_No response_

Start with the CreateUploadSession.PostAsync call in the supplied SyncFileOld method and compare it with the Microsoft Graph large-file-upload sample linked in the issue. Reproduce the upload using SDK version 5.73.0, then inspect the returned Invalid request and 401 responses. Done means identifying a reproducible cause and documenting or fixing the upload behavior.