The answer to 'gutter guards missing shingles' is that missing shingles on a roof with gutter guards can be caused by a few common issues. Gutter guards can sometimes interfere with proper shingle installation and cause the shingles to become loose or detach over time. This can also happen if the gutter guards are not properly secured or if the roof was not prepared correctly before the guards were installed.
Another potential cause is that the gutter guards themselves may have become damaged or worn out, leading to them no longer providing adequate protection for the shingles. In some cases, heavy rains, wind, or debris buildup can also dislodge the gutter guards and expose the shingles below.