Panthers don't munch on leaves like a veiled would do, but we're talking about individuals, you never know. Fake plants are risky and don't hold humidity, live plants are always the best choice.
Some of the links mention dead leaves. IDK if a chameleon knows or can tell the difference between dead and artificial, but I've never even thought of using artificial plants.
I have two panther chams. Both from completely different breeders (to prove its not hereditary) and I have seen both actually eat leaves before. One of mine is about 7 months and I saw him eat two leaves off of a vine plant I have when drinking water but he bit it and pulled the leaf clean off and ate it then went in for a second lol my other is almost a year old and he has bitten his pothos plant a few times. Can even see his bite marks on some leaves