TP-link T2600G-28TS not polling ports

When I add a TP-Link T2600G-28TS switch, the discovery module, finds all the ports, but, after the first run of the poller, all the ports are marked as "DELETED", so they won't be polled anymore.

Every 6 hours (when the discovery module runs), same thing happens: ports are discovered, but deleted after the first execution of the poller.

I have other TP-Link switches, but they are working fine.

Attached you can find execution of:

./discovery.php -d -m sensors -h XX

and 

./discovery.php -d -m os -h XX