The animation easing can be changed inside cocostudio UI editor, but it is ignored by the code. No easing is applied.
Easing is implemented, but NOT read from JSON.
This can be seen in method:
void ActionNode::initWithDictionary(const rapidjson::Value& dic,CCObject* root)
simply forcing an ease type, in any action frame, make easing work.
actionFrame->setEasingType( 3 ); //"3" -> sine in-out easing.
I suppose a future version will implement it
Just wanted to point this, for if it helps the developers.