Cannot cancel packing slip of moving average product in AX 2012.

I just created a released product and assigned a moving average inventory modle group to it. If there's no inventory for this product and it's physical negative allowed, the posted packing slip can be cancelled. But once there is inventory of this product, the posted packing slip cannot be cancelled, and an error pops up after clicking button 'Cancel'. Anyone met this problem before or has any solution? Thanks.Image may be NSFW.
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