Apprentice question
Verify first
Verify before you commit. Cheap to catch now.
Thermal movement needs somewhere to go. Replace the damaged section and add the approved expansion/flexible detail if the run is growing under heat.
['Warm discharge air can make long metal runs move. If the run is locked solid, wide flat-oval seams may take the stress and split.', 'Check temperature, run length, fixed points, supports, and whether an expansion coupling/flex connector is required. Replace split seam sections that cannot be restored mechanically.']