Sorry for the bump, but I just found a solution to this for anyone looking. This type of thing was unacceptable for my game, and I found the Roblox script you can modify to prevent the double bubbles. Basically preventing the bubble chat from copying what dialogs say. This also works for NPCs who you make talk using ChatService, just preventing bubblechat from duplicating things on non-player instances.
If you open up the BubbleChat script under Chat, scroll down to around line 650. You are looking for the function “OnGameChatMessage” This function is specifically for bubbles by game instances, not players.
I just added one line:
if true then return end
The reason we add the “if true then” is just so Roblox doesn’t highlight everything after the return statement. It isn’t exactly required, but makes the code editor a lot happier.
Another option is to just comment out this line:
Hope this helps anyone facing this issue!