On two consecutive normal flights, the batteries swelled and were difficult to remove from the drone until they cooled. Even after cooling down, the cooling vents remain blocked by the swollen cells. (See attached photos of normal open battery vents and a battery with blocked vents.) I subsequently noticed another battery that has never given me any trouble also has swollen and blocked vents. I have attached AirData deviation charts for all three batteries for your review. Would you fly with any or all of these batteries, blocked vents and all? I appreciate in advance everyone's feedback and advice.