I've had it do this to me once, and it planned to take me out of the path by two stars, before backtracking. I caught it before reaching that point of the course plot. After I had jumped a few times and re-plotted, it came up with something much more sane.
I occasionally run into another problem with longer course plots, where the course plot will fail without an apparent reason. If I shorten the course plot by a few hundred lightyears, jump a few times, then the plot may work straight to the intended destination. A few jumps later, it might fail again if I need to re-do it for some reason (like logging out for a short while).
Quirky, for sure, but usually these quirks can be worked around.