Hi @robbie
Please ignore my previous comment, I now see you had only included the inner loop. After adding in the outer loop, I can replicate the issue!
I have now fixed the issue and the function get_sub_field_object will now work with nested sub fields!
The fix is in api-template.php line 627:
$f = acf_get_sub_field( $field_name, $row['field'] );
That should fix the issue for now until the next version is out!
