Auto ML Model Builder Object detection - bad or no results

Windows 11 Surface Pro 8
- ML.NET Version 3.01
-NET 8

I have a selfmade training set of free hand drawn simple objects - black on white - circle, rect, triangle. Training with AutoML image classification works fast and detection results are very good.

I did a dataset vott image tagging. Created a single json file and ~150 images. Training with AutoML and Object Detection. Takes ~25minutes and results are unusable.
MAP50_95: 0,1258
Modell: ObjectDetectionMulti

Expected results is a better/good detection rate. I have no idea whats going on with my dataset. And how optimize it.
Side effect: Error Message from Visual Studio "no bbox detected" have to restart VS to rerun..

attached Json and sample image
[916a019c0896a9c18f5b7b2540b8014b-asset.json](https://github.com/dotnet/machinelearning/files/14191867/916a019c0896a9c18f5b7b2540b8014b-asset.json)