The answer to 'why is my soffit curling shingles' is that the most common cause is improper ventilation in the attic or roof space. When there is inadequate airflow, the heat and moisture buildup can cause the soffit panels and shingles to curl and warp over time.
Other potential causes include poor installation, damage from pests or weather, or just general aging and deterioration of the materials. If the curling is severe, it can lead to leaks, mold, and further damage to the roofing system.