The answer to 'flashing sagging' is that sagging roof flashing is a common roofing issue that can be caused by improper installation, deterioration over time, or damage from weather or other factors. Symptoms include visible gaps or separation between the flashing and roof surface, which can lead to leaks and water damage. To fix sagging flashing, the best solution is usually to have a professional roofer re-secure or replace the flashing properly.
While some minor flashing issues may be possible to DIY, it's generally recommended to have a licensed and experienced roofer address sagging flashing to ensure it's done correctly and safely. Improper flashing repair can lead to further roof damage, so it's important to call in a professional unless the problem is very minor.