Thanks so much @hotfoot and @JorgeB i had almost exactly the exact same experience (Also with a Adaptec 6805e moving to another case)
One difference was that my Main header was OK :
The primary GPT table is corrupt, but the backup appears OK, so that will be used.
Disk /dev/sdj: 7.28 TiB, 8001563222016 bytes, 15628053168 sectors
Disk model: WDC WD80EFZX-68U
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 17FE5483-ABCB-49BD-9E0D-A07F054DB25A
Device Start End Sectors Size Type
/dev/sdj1 64 15628053134 15628053071 7.3T Linux filesystem
root@Diskbox:~# gdisk /dev/sdj
GPT fdisk (gdisk) version 1.0.9.1
Caution! After loading partitions, the CRC doesn't check out!
Warning! Main partition table CRC mismatch! Loaded backup partition table
instead of main partition table!
Warning! One or more CRCs don't match. You should repair the disk!
Main header: OK
Backup header: OK
Main partition table: ERROR
Backup partition table: OK
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: damaged
i was also able to fix it with gdisk -> r -> c (this happened to 3 of the 9 disks in the array)
Once done i had to remove the device from the array and reassign it but everything is back to normal now.