The cracking issue when using the Joint Push/Pull tool in SketchUp is likely caused by geometric complexity, tolerance settings, or object intersection. By adjusting tolerance settings, using the "Snap" feature, dividing complex joints into simpler components, using the "Intersect Faces" tool, and updating to the latest version of SketchUp, users can minimize or resolve this issue. If the problem persists, it may be necessary to seek further assistance from Trimble Support or a SketchUp expert.