Consulta Select "compleja"

[bacc]

Si llevo esa misma consulta a la de JOINS queda así:

Código MySQL:

SELECT usrs_p7.id_padre, usrs_p7.id_informatica, usrs_p7.nivel, COUNT(usrs_p7.id_informatica)
 FROM usrs LEFT JOIN usrs_p1 ON usrs.id= usrs_p1.id_padre LEFT JOIN usrs_p2 ON usrs.id= usrs_p2.id_padre LEFT JOIN usrs_p3 ON usrs.id= usrs_p3.id_padre LEFT JOIN usrs_p4 ON usrs.id= usrs_p4.id_padre LEFT JOIN usrs_p5 ON usrs.id= usrs_p5.id_padre LEFT JOIN usrs_p6 ON usrs.id= usrs_p6.id_padre LEFT JOIN usrs_p7 ON usrs.id= usrs_p7.id_padre LEFT JOIN usrs_p8 ON usrs.id= usrs_p8.id_padre LEFT JOIN usrs_p9 ON usrs.id= usrs_p9.id_padre LEFT JOIN usrs_p10 ON usrs.id= usrs_p10.id_padre LEFT JOIN usrs_p11 ON usrs.id= usrs_p11.id_padre 
 WHERE (usrs_p7.id_informatica='1' AND usrs_p7.nivel>='1') OR (usrs_p7.id_informatica='9' AND usrs_p7.nivel>='1')
 GROUP BY (usrs_p7.id_padre)
 HAVING COUNT(usrs_p7.id_informatica) > 1;
 

Pero el resultado es este :
id_padre id_informatica nivel count(usrs_p7.id_informatica)
-------- -------------- ------ -------------------------------
3 1 3 8
4 1 3 12
6 1 3 2
7 1 3 2

Por que me devuelve 8 en el primer registro?