I have trouble recreating pen directionbug, but I managed to recreate brush direction bug in different scenario and I can reproduce it always.
https://dl.dropboxusercontent.com/u/268 ... pstbrushes
Above custom brush, has problem with 'angle1' property set to 'pen direction'. It works ok, when brush size is below 180, but when I increase brush size above 180px, pen direction is being ignored. Brush uses square alpha, with squeezeX.
And here are resuls of above brush with bigger spacing to better see the effect:

Left one - smaller brush size - work ok
Right one - bigger brush size - not ok.