Wrong Predictions came by SAHI

[Sparshj8287]

I use this command for prediction by SAHI
sahi predict --source /content/output_directory/data --dataset_json_path /content/output_directory/labels.json --slice_width 213 --slice_height 213 --overlap_height_ratio 0.2 --overlap_width_ratio 0.2 --model_confidence_threshold 0.25 --model_path /content/best_yolov8n.pt --model_type yolov8
This generate result.json in the output directory and I show one key value pair
[{"image_id":1,"bbox":[171.0547696314752,444.48016357421875,46.16821086779237,109.5960693359375],"score":0.2760390043258667,"category_id":21,"category_name":"bear","segmentation":[],"iscrowd":0,"area":5059}
So I do object detection and in my data there is only one class which is fish so why the result showing segmentation?