You rebooted, so the log doesn't show the spin downs for /dev/sda like you posted. Looks like you have the spin down set for every 15 minutes.
/dev/sda is a WD hard drive (WD60EFRX), so Unraid will spin it down. It doesn't appear to be a nvme SSD, but the sdX designation can change on reboot so that might not be right.
This is not really a UD issue.
You can filter the log messages by installing the Enhanced Log plugin and filtering these messages in the log 'Syslog Filter' tab of Enhanced Log.