The answer to 'why is my ridge vent curling shingles' is that improper installation or ventilation issues can cause the ridge vent to put excess pressure on the shingles, leading to curling and damage. This often happens when the ridge vent is not properly sealed or integrated with the roofing system, allowing air to escape unevenly and creating upward pressure on the shingles.
Some common causes include using the wrong type or size of ridge vent, not securing it tightly enough, or having inadequate attic ventilation that causes the ridge vent to work harder than it should. This can happen over time as the roof ages and the materials shift or deteriorate.