Pro Pioneer on 4.2.26 - New Drv 6 - Says Dead

Initially, I didn't hot replace; shutdown then replaced and hard rebooted
Then, I did a hot replace
Backup - no, its 9TB worth of info - nothing large enough to back up to
replacemtn drive was not formatted and came out of sealed Seagate packaging
yes, tried removing and re-inserting again with new drive
the unit display will say testing drive 6, then say passed, then notify of rebuilding in web front-end log; but then the unit display will show disk 6 failed - vol 6 unprotected
during the remove & replace - the web front-end will say that a disk was removed, new disk detected, then Data Volume will be rebuilt with disk 6
at the same time, the web front-end will show that disk 6 is dead in status, no temp reading
other than the 1 log entry saying that its rebuilding using disk 6, everywhere else shows disk 6 is dead and my volume is unprotected; nothing shows that its really doing the rebuild

I've run seatools against original disk 6 and replacement and neither drive shows up with any issues

confusing....