DIAGNOSIS No, it's likely not defective. The advertised 6-8 minutes is for subsequent cycles under ideal lab conditions (room temp ~70°F). Your first cycle or a cycle in a warmer room will always take significantly longer.
FIX First, optimize the environment. Move the ice maker to the coolest room in your house, away from heat sources. Ensure there's at least 4 inches of clearance on all sides for airflow. Second, always start with cold tap water in the reservoir, not room temperature water—this shaves off 5-10 minutes per cycle. Third, don't open the lid during a cycle; it lets warm air in and resets timers.
IF THAT DIDN'T WORK The compressor might be struggling due to a dirty condenser (the black grate on the back). Unplug the unit and use a vacuum cleaner brush attachment to gently remove dust and pet hair from the back grill.
HEADS UP In a room over 85°F (29°C), cycle times can double. This is normal for thermoelectric and compact compressor-based ice makers. It's a trade-off for portability.