Orion utilizes sysObjectID OID 126.96.36.199.188.8.131.52 and matches its value against built-in database of known SysObjectIDs to get vendor name and machine type, which is then displayed on Node Details page. Your device is returning "0.1", which does not seem to be a valid value for DELL. As Orion is collecting sysObjectID information periodically, as part of node rediscovery, value in DB gets overwritten because it is different than current value provided by device.
I recommend you to contact DELL support to find out if there are any updates or patches for available. Unless SNMP agent reports a valid sysObjectID, Orion won't be able to recognize the device correctly.