Not a good sign cloned disk not mounting with UD, but before trying to fix that lets see if you can emulate disk4:
-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all assignments and assign any missing disk(s) if needed, including the new disk4 and the cloned disk7, replacement disk4 should be same size or larger than the old one
-IMPORTANT - Check both "parity is already valid" and "maintenance mode" and start the array (note that the GUI will still show that data on parity disk(s) will be overwritten, this is normal as it doesn't account for the checkbox, but it won't be as long as it's checked)
-Stop array
-Unassign disk4
-Start array (in normal mode now), post new diags.