My right AirPod 2 heats up and is no longer detected.

A few days ago, I bought refurbished AirPods 2, it worked very well until today. I flew for more than 11 hours and when I landed, I noticed that my right AirPod was hot, so I took it out of the case and the left earphone. The right has cooled down, except that as soon as I put it back in charge, it gets hot again and I have the impression that it no longer charges.