1.
Seems to be a 180-degree bug in the game when when using waypoints. It has happend to me twice now but I saw it soon before it made much damage. If you are sailing with waypoints and plan to add more later beware of the bug. If you are passing a waypoint when in the game when you plan more waypoints the first waypoint may not be erased when you pass it. So when the game updates it turns your boat 180 dergrees to that waypoint!
I do not know if it really do that but I did not wait and see. To much time to loose if so.
Not good if it did that. So to fix it you have to place the latest waypoint ahead of your track again or erase all and place them again.
2.
Another thing if you follow your track is that after passing a waypoint it seems that it made the turn early and the track shows you have sailed true downwind for an hour or so. This maybe be a track rounding in the game but who knows. Not optimal to sail true downwind...