Unexpected LineJoinStyle behavior when lines in path at 180 degrees

I'm getting a clipped LineJoin in a UIBezierPath when one line comes back exactly over the previous line. If I adjust the second line by one pixel, the LineJoin behaves as expected. Here's the code: ``` UIBezierPath *path = [UIBezierPath bezierPath]; [path setLineWidth:10.0f]; [path setLineCapStyle:kCGLineCapRound]; [path setLineJoinStyle:kCGLineJoinRound]; [path moveToPoint:CGPointMake(100, 100)]; [path addLineToPoint:CGPointMake(200, 100)]; [path addLineToPoint:CGPointMake(150, 100)]; [path moveToPoint:CGPointMake(100, 120)]; [path addLineToPoint:CGPointMake(200, 120)]; [path addLineToPoint:CGPointMake(150, 121)]; [[UIColor redColor] setStroke]; [path stroke]; ``` Here's what's displayed: Is this a bug? If not, is there some way to get the top path LineJoin to be rounded? (without fudging the points) This came up when I made a UIBezierPath from 'touch-input', and while scribbling around sometimes this happened.