The answer to 'why is my architectural shingles leaking' is that there are several common causes, including improper installation, age and wear, and damage from weather or impact. Symptoms may include visible cracks, curling, or missing shingles, as well as water stains or leaks inside the home.
In many cases, leaks from architectural shingles can be repaired with some DIY work, such as replacing individual damaged shingles or sealing cracks. However, if the issue is more widespread or caused by underlying structural problems, it's best to call in a professional roofing contractor to properly diagnose and address the root cause.