External HDD powers down and (almost) immediately up again

Nextcloud version
Nextcloud pi version 1.37.0
Raspberry Pi OS
Apache 2.4.38
PHP version 7.3

Likely through the last update onto my current NC version I have an issue with the powersaving on my external USB-drive. HD-Idle used to work fine for me: it powered down the HDD most of the time of the day. However now the harddisk powers down and wakes up a minute later. Has anyone an idea what the reason might be or even how to fix it? Thank you.
Kind regards