After upgrading my system to Windows 11 my legacy disk goes offline when resuming from standby mode. It appears that the error described here which has apperently been fixed in Driver version 9.3.0.00266 is back under Windows 11.
My system consists of an ASUS X570-PLUS, AMD X570 chipset. Two drives working in RAID 1 mode (which are working fine after resuming from standby). One drive is working in legacy mode. Driver is up to date (version 9.3.0.00266).
AMD support states that this is none of their business. I should reach out to Microsoft or ASUS.