Kindly complaint to Samsung customer support through Samsung Members App as error report for this issue. Then go to service center for repaste it's. If you like please accept as a solution it's help to others users also, click on 3dots in my reply section and click on accept solution. Thanks.
Common issue with Samsung devices, seems like their Exynos division making the glue 😉. Anyway ask the service centre to glue the back panel, they usually does it for free. If they are charging then go to any local repair centre and ask them the same or you can buy E8000 glue online to do it yourself. Don't bother replacing the back panel even if Samsung care people ask you to do that, this issue will happen again.
If Your Phone Is in Warranty Go To Service Center And If Not In Warranty Go To Local Mobile Shop And Tell To Paste It With The Gel Glue And Bind With Rubberband Nicely For2 to 3 hours
