Mojave 10.14.6 - SMART USB
My main machine for a couple of months is a mac mini 2008 and even if in SoftRAID the option "Enable SMART on USB disks" was on it actually didn't do anything. There was no SMART reporting from any USB drive and the right click option to enable or disable SMART on a specific USB drive i think was greyed out. Because i know it worked in the past on my Macbook Pro with High Sierra and i only used Mojave on the new mac mini i thought the option doesnt work on Mojave.
Yesterday i updated to 10.14.6 and everything went havok. So if you have USB disks and you sudden errors after the update (my culprits are the WD Elements 5TB which are discussed here: https://srforums.wpengine.com/forum/showthread.php?tid=784) make sure you disable at least the USB SMART on those disks.
10.14.6 unlocked SMART on my system probably with a silent firmware upgrade which is a good thing but a pain if you own incompatible drives.
Some USB disks do not respond to SMART queries, or respond badly. Also, Mojave sometimes "quarantines" the SoftRAID SMART driver, so it does not load (so you do not see the USB SMART data)