Yeelight local API problem

Hello, I’m developing a Yeelight local control API wrapper in Java and I encountered a problem.

When I send a control packet to control the light, the light doesn’t reply to it (it sends a notification packet but not a result packet). It can be seen on the telnet screenshot below:
or even my logs:

As the official specification says:

Every command message should expect a result message.

(page 19)

Why doesn’t it work then?