The answer to 'flashing missing shingles' is that missing or damaged flashing is a common cause of missing shingles. Flashing is the thin metal or plastic material used to seal around roof penetrations like chimneys, vents, and skylights. If the flashing is missing, cracked, or not properly sealed, it can allow water to get under the shingles and cause them to come loose or blow off.
Some common symptoms of missing or damaged flashing include water stains on the ceiling, mold or mildew growth, and shingles that are curling, cracking, or missing. The solution is to have a professional roofer inspect the roof and replace any missing or damaged flashing. This is typically a job best left to the pros, as it requires specialized tools and knowledge to properly install new flashing.