Metrics appear in the SLM and are present in the database.
The problem is that the devices do not appear in the portal inventory.
Problem solved by selecting "Force component rediscovery":
- go into snmpcollector
- click the profile for one device
- select "Force component rediscovery".
This often results in the device appearing in USM a few minutes later as it forces a realignment of the ci_metric_id values.