Postgres look for relation with wrong name

In Postgres I have the following tables:

CREATE TABLE punching_history (
    id_punching serial NOT NULL,
    punching_date timestamp without time zone,
    -- other fields
    CONSTRAINT punching_pk PRIMARY KEY (id_punching)
);

CREATE TABLE punching()
INHERITS (punching_history);

and this sequence (auto generated by serial field of punching_history):

CREATE SEQUENCE punching_history_id_punching_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 9223372036854775807
START 1
CACHE 1;

The insert (persist) into punching table works, but sometimes, apparently without reason, it fails with this error:

"HTTP 500 Internal Server Error - could not extract ResultSet 
org.postgresql.util.PSQLException: ERROR: relation 
<schema_name>.punching_id_punching_seq does not exist Position: 16"

In Hibernate primary key is mapped as:

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID_PUNCHING", unique = true, nullable = false)
private Integer idPunching;

Why does Postgres look for punching_id_punching_seq relation? It has always been punching_history_id_punching_seq.

Thanks