The answer to 'gutter guards missing shingles' is that missing or damaged shingles are often caused by improperly installed gutter guards. Gutter guards that are not properly secured or that are the wrong size for your gutters can interfere with the shingles, leading to them becoming loose or detached. This can allow water to seep under the shingles and cause further damage to your roof.
In some cases, the weight of the gutter guards themselves can also put stress on the shingles, causing them to become dislodged over time. If you notice any missing or damaged shingles, it's important to inspect your gutter guards and make any necessary adjustments or repairs to prevent further issues.