http://forums.autodesk.com/t5/Autodesk-Inventor/Deleted-parameter-Thickness-being-inserted-into-iLog...
Whenever I delete a feature from a sheet metal part that contains an iLogic rule, Inventor sticks the following turds into the beginning of my iLogic rule. Whenever this happens it causes an error in my rule, forcing me to go back and remove these turds from my rule.