We have been seeing similar issues lately. If you have a support contract I recommend you contact LANDESK Support.
We also have this same issue. A fix would be nice.
Thanks for bringing this concern to our attention. A successful "ping" response does not validate whether or not Landesk can discover a machine. It does validate the machine being online. What we are looking for is a "pong response" when we attempt to discover. This validates that the Landesk Management Agent service on the target device is functioning properly and will pull back from the client all pertinent inventory information relative to the discovery process (guid,ip,device id etc). You can perform the following test from the core in efforts to see if you receive a "pong response" from the client:
From an admin cmd prompt navigate to the ManagementSuite directory location and execute:
pds2dis.exe ping ip_address_of_your_target
If you don't get a pong response, discovery will fail. You can try restarting the Landesk Managementsuite Agent service on the client and re-perform your test. You can further troubleshoot this activity by running a wireshark trace from the client while attempting to discover from the core,in efforts to determine whether or not the communication attempt even made it to the client. If you would like the wireshark trace or any other test you've performed further reviewed please contact support and we will get you squared away.