That sounds to me like those ships are missing transponder data for some reason, and the visualisation is extrapolating between to distant data points.
Not sure why this would be the case. Transponder turned off? Data missing for other reasons?
I've never seen a perfectly clean dataset of any significant size. Big datasets have all sorts of weirdness unless there was an extraordinary effort to keep them pristine.
Not sure why this would be the case. Transponder turned off? Data missing for other reasons?