I'm unfamiliar with that transmitter, but I see it does have mixing, I think this is your problem. Try one esc at a time to eliminate this. If it was a plane for example, you would have to set that sort of v tail in the setting, or it would not work. I have spectrum, and can see on a digital picture the movement of the channel operation when in use, if the futaba has that feature, then this will tell you what is happening when it all goes wrong.
I suspect you need to dial in a mix to make it work. I'm sure youtube will have the answer in there somewhere, at least illuminate the dual esc thing, then you know they should work. The tx is just not telling them the correct programme