Headphone jack rubber melted

Hi, i have a question. Im fixing a galaxy note 10.1 for a friend. While im checking the tablet i found that rubber cover around the headphone jack is totally melted! Even the tablet is off.. the rubber is totally melted like a glue.. and it came off. I have a pic of it.. but i could attach it here. Can i know why this happens? Is it because of short circuit? Or motherboard problem? Thanks a lot. If you would like the picture of it. Please email me @ izafarhana89@gmail.com