NPM reports Device already in OrionDB, but it is not

We are running NPM 11.5.2. We are attempting to import 10 Windows devices into NPM.  The discovery is successful.  When we go to import the devices, NPM says these devices already exist in the OrionDB.  We have checked the Nodes table and the devices definitely do not exist in the DB by name OR IP address.  They are also only single NIC devices.  We ran the configuration wizard as well as Database Maintenance and reran the discovery and import process with the same results.  We again verified that the devices do not exist in Managed Nodes and the Nodes table of the DB by caption name OR IP address.  We ARE able to manually add the devices to Orion without any problem.

Has anyone seen this issue before and might know what is causing the problem?