Was it perhaps a gusty day, with variable wind directions? If so, you may just have been unlucky.
Wow you are a nice guy, haven't been around long have you.
It could be just bad luck but my current theory is that I was pinching it so much that my speed slowed to the point where the current was having its way with me.
I'm going to review the track log again and check my speed. I remember checking the gps and if I remember correctly I was doing at least 3knots.
That may not help my theory though.