If it charges fine then the issue may be with the led board that you have in the magnetic charger plug. Replacing the charger cable would probably solve the issue, since the Mac part of the charging circuit works fine with another charger, if I got right. I’d just install Coconut battery App to check the correct power is supplied to the Mac, but if that is right comparing the two chargers data then it would only be more of a cosmetic matter. Even if unrequested, I’d stress once more the risks of dealing with the inners of a Magsafe..charged capacitors can indeed stop one’s heart beat, they are very very dangerous beasts.