AutoCAD Inventor :: Project Cut Edges Error

I found a weird thing with the command 'Project Cut Edges'. I'll explain what I did. I made a new part and added a derived part. This derived part consists of 2 beams (see top left picture in attachment) (these beams are NOT Content Center parts, but I drew the beams myself, so it would be the same if I drew just rectangles as beams). The beams are at a specified distance of each other (see top right picture in attachment). I added a sketch on the YZ Plane and clicked on 'Project Cut Edges' (see bottom left picture in attachment). I added a rectangle and extruded the rectangle. But if I click on the 'Project Cut Edges' item in the browser under Sketch (or I open the Sketch), not all the lines are there anymore. And if I make the distance between the beams smaller, the lines get shorter too (and vice versa).