strange bug animating line width

[BA]

can't for the life of me figure out what's going on here...


I am animating the line width of a drawing, slowly bringing it up from zero.

Started by creating the drawing with the final line width, then created a frame in which all points have a line width of zero.

The first time I did this, I did it by dragging all selected points with the line width tool down to zero. When I did this I went back to the keyframe I'd set previously, with the proper line widths, and noticed that a few seemingly random points were now holding at zero width. Even though I'd set a keyframe for them at full width, they never scaled back up from zero. Keep in mind that most of the other points scaled properly, and there was no discernible order to the ones that didn't work.

So I undid, went back and instead of using the drag tool I set the line width to zero numerically at the desired keyframe. Went back to the keyframe with full width, and now it looked fine. But then I noticed - a number of the points were not animating the change in line width. In fact, immediately after the first frame (zero width), on the next frame they jump to their full size.

The weirdest part of it all is that the points in question were the same ones that had problems the first time around.

What the hell is going on????

[BA]

note - this has also happened on another layer, totally different shape.