One reason it could go "caflooey", is if the parent element is scaled, and uses 'propagatingScale' channels, rather than 'scale' channels, this would cause the child to addopt the scale of the parent, this could have particularly bizzar results if any rotations are applied to the child. If this is the cause of the problem, one solution is to open the parent item in a text editor and do a global Search and Replace of the string "propagatingScale" with "scale" (case sensitive). Do this on a copy so as not to damage the original. If scaling opf the stick is the cause, another solution would be to export the scaled stick as an object, then reimport it, and parent your mask to that.