Problems with Pathfinder altering shapes

Question

I haven't used Pathfinder in a while, but have recently and run into problems.
It seems to alter shapes and add stroke value instead of just slicing things apart (using the divide tool).
I've tried expanding strokes, removing strokes etc... but are there any other values I should try to reduce before dividing?
I attached a few samples. The "after" actually alters the smooth shape of an ellipse by angling the points. It also bloats up the weight of the white lines.
Is there a checklist of things I should make sure I have off, like compound paths, expanding strokes, etc?
(in this case, I turned the stroke off)

Answer 1

DB,
Another Guess, here. Try checking the Pathfinder Options, maybe the value is too high. I never have touch these settings but was able to replicate your issue quickly by increasing the number. I know little about them but maybe that's where illy had it's "boom-boom".
Goodluck!
dB
databang