Strange behavior

[It may be a repost, I had a little mess in my mail last weeks, sorry]

I tried to make a simple select on a single table and I find some
strange results.

First of all I execute the following query :

=> select crit_url from crit where crit_url like 'films/%' order by crit_url;

crit_url
-------------------------------------
films/7-samurai.html

[...]

films/victor-pendant-qu-il.html
films/violent-cop.html
films/wild-things.html
(53 rows)

Now if it try this one :

select crit_url from crit where crit_url like '%films/%' order by crit_url;

crit_url
-------------------------------------
films/7-samurai.html

[...]

films/victor-pendant-qu-il.html
films/violent-cop.html
films/wild-things.html
films/y-aura-t-il-de-la-neige.html
films/you-ve-got-mail.html#ab
films/you-ve-got-mail.html#fvd
films/you-ve-got-mail.html#fvd
films/you-ve-got-mail.html#thb
(58 rows)

As you can notice there is 5 more rows in the second query that in the
first and, as far as my SQL understanding goes, they should have in
the first selection. Since there is an index (partly) on crit_url I
tried to remove it but it does change anything. Any idea ?

lumiere=> \d crit

Table = crit
+----------------------------------+----------------------------------+-------+
| Field | Type | Length|
+----------------------------------+----------------------------------+-------+
| crit_id | int4 not null default nextval('c | 4 |
| films_id | int4 not null | 4 |
| crit_texte | text | var |
| crit_date | date | 4 |
| crit_url | text | var |
+----------------------------------+----------------------------------+-------+
Indices: crit_crit_id_key
crit_skey
lumiere=> \d crit_crit_id_key

Table = crit_crit_id_key
+----------------------------------+----------------------------------+-------+
| Field | Type | Length|
+----------------------------------+----------------------------------+-------+
| crit_id | int4 | 4 |
+----------------------------------+----------------------------------+-------+
lumiere=> \d crit_skey

Table = crit_skey
+----------------------------------+----------------------------------+-------+
| Field | Type | Length|
+----------------------------------+----------------------------------+-------+
| films_id | int4 | 4 |
| crit_url | text | var |
+----------------------------------+----------------------------------+-------+