New devices are discovered but no data is polled.
Reviewing the devices in the Monitored Devices Inventory, on the Polled Metric Families tab none show as Supported or Not Supported. All fields are missing the expected information.
A specific cause was unable to be determined. According to the logging engineering believes that the Data Collectors responsible for the discovery of the devices took too long to respond to the Data Aggregator. The messages it should have transferred to the Data Aggregator expired and were never re-processed.
Performance Management release r3.7.10
A restart of the Data Aggregator and Data Collector(s) involved resolved the issue.
After that within 24-48 hours when the Monitoring Profile Change Detection cycles ran on the devices the Certifications that should be supported now show as Supported.
After that they began being polled and data showed up for the new devices.
Reproduction while debug is enabled, which wasn't able to be seen here, would provide engineering with new clues that might help to determine a true root cause.