Problem annotations in OBB yolo format: negative coordinates?

I have annotated an image with Roboflow tool (polygon BB) (I have the same problem when importing labels from not roboflow tool)
In Raw data, “boxes” label coordinates are OK.
But when I export the annotations in YOLOv5 OBB format the .txt file makes no sense, even with negative coordinates:
-4.205982306939404 20.480524948844938 4.830673360356741 9.525526396235675 418.4850314081814 150.3811808413242 409.4486719996894 161.33601570943324 art 0

Any idea? I can not even reproduce the Roboflow tutorial about OBB since when I import the dataset it happens the same problem (negative coordinates in the OBB)