After I bought a new charger and cord to replace the "deteriorated" cord, I discovered this AM that the new cord has the same "problem" as the old one! My recently adopted rescue kitty is apparently the culprit! (She has become a rather expensive pet! Fortunately, I found some deterrents on line.)
Ugh, ours did that too, but with iPhone & iPad cables. Had to get these cord covers, plus spray them with bitter spray.