如果我执行这个简单的查询

SELECT * 
FROM (
  SELECT 'abc' AS name 
  UNION ALL 
  SELECT 'abc d' AS name
) AS test 
ORDER BY name;

我得到了如下结果（正如预期的那样）：

name
-------
 abc
 abc d
(2 rows)

即串abc d的空格字符被认为大于串abc的结尾。
到这里一切都很好。
接下来，如果我尝试：

SELECT * FROM (
  SELECT '{"name":"AbC"}'::JSON AS json
  UNION ALL
  SELECT '{"name":"aBc D"}'::JSON AS json
) AS test ORDER BY LOWER((json -> 'name')::TEXT);

我得到：

json
------------------
 {"name":"aBc D"}
 {"name":"AbC"}
(2 rows)

这次字符串abc d的空格字符被认为比abc的字符串**的末尾小!
我还尝试了：

SELECT * 
FROM (
  SELECT 'abc'::TEXT AS name 
  UNION ALL SELECT 'abc d'::TEXT AS name
) AS test 
ORDER BY name;

SELECT * 
FROM (
  SELECT 'abc' AS name 
  UNION ALL 
  SELECT 'abc d' AS name
) AS test 
ORDER BY LOWER(name);

SELECT * 
FROM (
  SELECT 'abc'::TEXT AS name 
  UNION ALL 
  SELECT 'abc d'::TEXT AS name
) AS test 
ORDER BY LOWER(name);

并且它们都给出了预期的结果。
我也试过：

SELECT * FROM (
  SELECT '{"name":"abc"}'::JSON AS json
  UNION ALL
  SELECT '{"name":"abc d"}'::JSON AS json
) AS test 
ORDER BY (json -> 'name')::TEXT;

其也考虑小于字符串结尾的空格字符。
看起来 * unexpected * 行为是由JSON字段的字符串属性转换为（任何？）postgres字符串类型引起的。我试图在PostrgeSQL文档中搜索此现象的原因，但我无法搜索到。
有人能告诉我关于这个的文档吗？或者我们应该认为这是一个bug？