Yeah, I am really surprised that Echo came out with a duplicating ult that doesn’t have the same problems as other duplicating heroes in other games.
Sylas is another example, but he can only steal ults but some ults in LoL changes the abilities of the champion as well like Jayce. I am not the one that are in too deep with LoL but no one seems to complained about Sylas having bugs relating to duplicating.
I wish the same can be said about Dota 2 though. Morphling has the ability to turn itself into another hero and in classic Valve half butt nature, there was a bug where if Morphling copies a hero when he came back the hotkeys will be ****. Sometimes it even happened in reversed.