Yes, in the same slot, i.e., disk5, not disk6.
From what I can see disk5 was formatted:
Jun 23 10:25:02 Tower emhttpd: shcmd (101): mkfs.xfs -m crc=1,finobt=1 -f /dev/md5
So there won't be anything to rebuild, to confirm re-assign disk5 to disk6 slot and start the array, then post new diags.