this node http://opennms.si.tnnet.it:8980/opennms/element/node.jsp?node=2066 have had a problem with SNMP agent and so it don't have Resource Graphs.
We had a problem with a wrong configured snmp agent for a node with direct provisioned SNMP service.
The data collection was failing and also the SNMP protocol from poller was Down.
We fix the problem with the snmp configuration and we have forced a node rescan.
SNMP service went UP, the SNMP attributes are right and node has a valid backup on rancid, but the node even don't has Resource Graphs.
It seems that the data collection is not started.
In Instrumentation Log reader I don't find the SNMP primary of this node: 10.25.132.213
Restarting opennms fix the problem