It's annoying, but that's the normal behavior. I guess it has something to do with the Vita's USB charging feature.
But like I said, it also happens with other devices like my set-top box and HDMI switch (which isn't even connected to the power strip but to the TV via USB cable [and HDMI cable]) so I prefer to click the power strip's switch but the difference is that the PS TV only has this behavior sometimes unlike the set-top box and the HDMI switch. PS Vita or PS TV? Anyway, how can that feature cause this behavior when it's not even being used and why does it cause it only sometimes? Also, what causes this behavior in the set-top box and HDMI switch?
Describe this weird noise, if it's like a clicking sound, the drive is probably dying.
It's an annoying whistling noise.
When connecting the PS5's Seagate 3.5" 8 TB external HDD to the PS5 it makes this noise even if the PS5 is turned off.
I already had this problem when the external HDD was connected to my PS4 Pro. Does that mean the external HDD may stop working, or even worse, may it fry all my devices connected to the power strip (like the PS5, its external HDD and other devices) or/and may it even start a fire? I only bought the external HDD somewhat over two years ago (at the time for the PS4 Pro) and I've had this problem since then. Meanwhile, the warranty has expired.
If I connect the external HDD to the laptop or to a socket in another wall I don't have this noise.
EDIT: I'll stop clicking the PS5's external HDD's power strip's switch overnight because after doing it next time, the HDMI switch (which isn't even connected to the power strip but to the TV via USB cable [and HDMI cable]), the set-top box and sometimes (which I also find it odd) the PS TV automatically turn on afterwards.
Also, it seems the PS5's external HDD is making a second noise even with the PS5 turned off and I have to click its power strip's switch or take its power cord to stop it as well.
EDIT 2: I might take the PS5's external HDD's power cord from the external HDD's power input from now on to stop these noises even if playing PS4 games on the PS5 will take longer since it will take some time to recognize the external HDD to load the PS4 games on it or to recognize the external HDD to install new PS4 games to it.