Many have the same issue, rarely it's the battery. In my case there is a component on the main board of the controller which when heated up with a heat gun, it will partially cure this issue. There are videos online,
showing the process. I have heated, the videos call it re-flowing, my controller multiple times but the controller would eventually revert back and would only charger to 76%, but even that charge would only last 4 batteries flying time. I've read that some have sent their out of warranty controllers back to DJI and they get it repaired for $90. I finally sent mine back a few weeks ago, coming back to me tomorrow. I'm not sure if I'll get my controller back or a refurbished one. The repair says battery replaced, we'll see. I'll update when I get it back