Some (more than 10) correctly configured SNMP profiles cannot be selected in Discovery Profile configuration or in the Device admin settings on the Details tab.
A full re-sync of the Data Aggregator does not solve this problem.
The correct SNMP Profiles are present on the Manage SNMP Profiles page.
All supported DX NetOps Performance Management releases
Note that after this process the Global Sync cycles may take an hour or more processing the changes as a result of the fix.