The answer to 'why is my air filter blowing cold air' is that the air filter may be frozen or obstructed, causing cold air to blow through it. This can happen if the HVAC system is not operating properly, or if the filter is clogged with dust and debris.
Some common causes include low refrigerant levels, a malfunctioning blower motor, or a blocked airflow. In some cases, the filter itself may be frozen due to the system running too long or at too low a temperature. This restricts airflow and causes the cold air to blow directly through the filter.