Ask HN: Is the following a poosible privacy issue in the WeChat app?

One of my friends uses WeChat. He shared with me how certain phrases entered into the chat rextbox trigger a certain animation on the screen. Phrases such as "I love you", "I miss you" etc trigger it, but not normal phrases.

This must mean that the app is monitoring the text being entered into the textbox. Isn't this a possible privacy issue? If yes, why isn't this being discussed yet?