Bind and DLZ strange loop

[Job]

Hello,

we use Bind with DLZ, Postgres 8.4.8 as RDBMS support.

Everything works but, with DLZ query, i notice (in Postsgresql log), that Bind calls two times the same queries.

For example, to resolve with Bind-DLZ www.fiorino.it, it should make three queries (to descend until Top level domain):
www.fiorino.it
fiorino.it
it

Instead of this, it repeat the queries two times:

first time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.965 ms  statement: select 'www.fiorino.it' where function_cloud_view_orari('53', x.x.x.x, 'www.fiorino.it') != '';
first time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.359 ms  statement: select 'fiorino.it' where function_cloud_view_orari('53', x.x.x.x, 'fiorino.it') != '';
first time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.304 ms  statement: select 'it' where function_cloud_view_orari('53', x.x.x.x, 'it') != '';
second time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.291 ms  statement: select 'www.fiorino.it' where function_cloud_view_orari('53', x.x.x.x, 'www.fiorino.it') != '';
second time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.291 ms  statement: select 'fiorino.it' where function_cloud_view_orari('53', x.x.x.x, 'fiorino.it') != '';
second time <2016-09-07 17:36:56 CEST>LOG:  duration: 0.215 ms  statement: select 'it' where function_cloud_view_orari('53', x.x.x.x, 'it') != '';

Can someone help me with?

Thank you!
Francesco