hdparm disk spin-down not working anymore

My setup: Raspberry 4 / Raspberry OS; additional 3TB WD HDD attached via USB3 I was using hdparm to spin down this harddisk after 3o min. This **was working perfectly fine** until few days ago. Now, there was a power outage that caused the raspi to reboot, and since then the hdparm command just stopped working. Here is the output:

root@raspi:/ # hdparm -S /dev/sdb
  -S: bad/missing standby-interval value (0..255)
	
root@raspi:/ # hdparm -S 36 /dev/sdb
/dev/sdb:
 setting standby to 36 (3 minutes)
 
root@sraspi:/ # hdparm -S /dev/sdb
  -S: bad/missing standby-interval value (0..255)

The drive is not spinning down after 3 min. Smartmontools say the disk is healthy, also some samba shares on the disk work fine. And like I said, before the power outage and forced reboot all was ok. Anybody has an idea what's the problem here??? **Update:** I tried to use sdparm, result:

root@raspi:/ # sdparm --all /dev/sdb
    /dev/sdb: asmedia   ASM1153E          0   
Write parameters (MMC) mode page:
  BUFE          0  [cha: n, def:  0, sav:  0]
root@raspi:/ #

This is very weird for me again: 1. it says ASM1153E, which is my USB controller, but wasn't sdparm supposed to talk directly to the harddisk??? 2. there are parameters missing, especially SCT and STANDBY which I intended to use (maybe because of 1.??) Any help or thoughts are very appreciated