BUG #13711: Error creating index on ltree column

The following bug has been logged on the website:

Bug reference:      13711
Logged by:          Cstdenis
Email address:      cstdenis@ctgameinfo.com
PostgreSQL version: 9.2.13
Operating system:   FreeBSD 10.1
Description:

CREATE INDEX user_comments_id_tree ON user_comments USING gist (id_tree);

ERROR: failed to add item to index page in "user_comments_id_tree"
SQL state: XX000


I have another database with identical schema with no problems, but when I
try to restore the backup of this one on a new server the restore has this
error with 2 indexes on this column.


Some info about the data:

fanart_central=# Select count(id_tree) from user_comments;
  count
---------
 6650726
(1 row)


fanart_central=# Select max(nlevel(id_tree)) from user_comments;
 max
-----
 183
(1 row)


fanart_central=# Select max(bit_length(ltree2text(id_tree))),
max(char_length(ltree2text(id_tree))) from user_comments;
  max  | max
-------+------
 11704 | 1463
(1 row)


Table definition:
CREATE TABLE user_comments
(
  comment_id serial NOT NULL,
<snip>
-- Inherited from table base_comments:  id_tree ltree NOT NULL DEFAULT
''::ltree
)
INHERITS (base_comments)