sometimes in corel if you import a vector drom somewhere else, it may have 1,2, or 3 lines overlaid on the same line used to cut. so the plotter cut each one........
do like bill said get it to wire frame, ungroup it and put the cursor on a line and hit delete, if the object is still there, hit delete again...or as many times as it takes for it to go completely away, then do a control +z to bring only 1 back in place. you will have to do this with all the lines that woulda been cut.