The answer to 'roof vent curling' is that it is a common issue caused by exposure to the elements over time. Roof vents can curl or warp due to heat, UV radiation, and weather conditions, which can compromise their effectiveness and lead to leaks or other problems.
Symptoms of a curling roof vent include visible warping or bending of the vent, gaps around the base, and reduced airflow. To address this issue, you may be able to try a DIY repair by re-sealing the vent or replacing the vent cap, but in more severe cases, it's best to call a professional roofer to inspect the vent and determine if a full replacement is necessary.