When installation error meets improperly made materials.
This aluminum elbow was cast incorrectly, leading to an extremely rough surface. Unfortunately for the customer, the installer did not notice. When the bolt was tightened to attach the plastic shroud, the jagged rises on the elbow broke the normally stout plastic shroud tab.
Instead of simply replacing what is broken, it’s imperative to investigate the cause of the break. Had the damaged plastic been swapped without also ordering a properly produced elbow, the break would have occurred once again.