Disk 2 (an 8TB drive) was being emulated. I replaced the drive with a 10TB. I then started preclearing the 8TB drive. It got all the way through Pre-Read but is randomly disappearing from the unassigned devices list when it started zeroing and showing up as "not installed" under historical devices. Maybe it was happening during the pre-read as well I didn't notice though. See the diagnostics attached. Thanks.
rehoboam-diagnostics-20211129-1535.zip