json_query conditional wrapper bug

These are ok:

select json_query('{"a": 1, "b": 42}'::jsonb, 'lax $.b' without wrapper);
  json_query
------------
  42

select json_query('{"a": 1, "b": 42}'::jsonb, 'lax $.b' with 
unconditional wrapper);
  json_query
------------
  [42]

But this appears to be wrong:

select json_query('{"a": 1, "b": 42}'::jsonb, 'lax $.b' with conditional 
wrapper);
  json_query
------------
  [42]

This should return an unwrapped 42.