The Discovery process may fail with an error on the pattern logs where you can see:
"Identification CI Errors: Abandoned due to too many errors".
This is most likely caused by duplicates on the relationship type table [cmdb_rel_type].
1 - Enable the Debug for the CI Identification parameter on the Discovery properties ( glide.discovery.debug.ci_identification ).
2 - Quick discovery the affected device.
3 - Check the logs on the syslog_list.do, the CI Identification ones would be like:
identification_engine : DUPLICATE_RELATIONSHIP_TYPES Duplicate relationship type records exists with name [Master of::Stack Member of]
4 - Figure out which relationship type has got duplicates. Go to cmdb_rel_type_list.do and filter by name, there should be only one record for the same type.
5 - Check on the cmdb_ci_rel_list.do if there is any relationship using that particular type, in which case a deletion would break the link.
6 - Delete the record that is not being used.