When a device is discovered in SapphireIMS, it will be checked against number of available licenses to make this node as managed. If not enough license available, then the node will go into unlicensed state. Please note that number of license entitlement for agent and agent less device is different and may vary depending on number of agent and agent less devices to be discovered and accordingly customer can procure the license.
If node is discovered in agent-less mode and went to unlicensed, then such devices will list under Unlicensed devices. If node is discovered in agent-based mode and went to unlicensed, then it will list under Agent Unlicensed devices.
To know how about license limit and utilization, please visit page SapphireIMS License Usage