If the front plug of your LEVIA stick appears melted or deformed (the part that goes inside the device), your device is perfectly fine. This happens because the stick is not perfectly or fully inserted in the device. Please, check if the melted front plug is not stuck inside the device and remove it before the next use.
To ensure you do not face this issue in the future, please, correctly insert the LEVIA stick to the line on the filter, with coloured part facing outside.