Fade on or off with Yeelight Lightstrip Pro

My account is 1691851030
Server: Chinese mainland
1s firmware version : 2.1.7_0020
pro firmware version: 2.1.7_0021

I have Yeelight Lightstrip 1s and Yeelight Lightstrip Pro. The 1s is can fade in or out while turned on or off. But Yeelight Pro can only do fade on effect. When i try to turn off it just turned off without any fade effect. Can you help me with that ?