Only some bounding boxes drawn in output video

[rebeccamart]

Hi,
When I run the object_tracker.py file, I get the output video correctly, but I can only visualize some bounding boxes.
For example, in the first frames, it counts 13 tracked objects, but the box does not appear, it is not drawn in the video.
Nevertheless, in other frames of the same video, the bounding boxes appear.
Does anyone know why or could help? Thanks in advance.