When the SOI APM connector receives more than about 15 alerts at a time from APM it starts to drop alerts.
We are currently running version 3.2.0 of the connector but this was also happening with previous versions.
Limited buffer size in connector code
APM connector version 3.4.1
which can be downloaded at
https://support.ca.com/us/product-content/recommended-reading/technical-document-index/ca-service-operations-insight-connectors.html