TL-D800C won't spindown or sleep HDDs after host system get shutdown

Hi, I use TL-D800c on OpenMediaVault System [debian 12, bookworm]
When I shutdown host system, HDDs in TL-D800C keep spinning up

I have 6hdds in TL-D800c, When I turn off host system only 1~2 HDD gets spin down [I hear spin-down sounds just 1~2 time] after few minutes, but others keep spinning after 20minutes

I can check this through smart plug [with power monitoring], TL-D800c spends around 40w~ after host system’s power-off.

I want to know who have similar issues with TL-D800C and
share ideas to solve this issue

I started recently to control power of TL-D800c through smart plug [IOT switch plug]
after my host system shut-down, wait 1~2mins, then turn off power switch through smart plug…
Through smart plug switch, I can handle this problem but I believe there is more easy way to get through this issue…