newrelic – Not all requests are captured (randomly)

During load testing on an isolated server, not all requests are captured.
I have a load testing that executed requests to 2 specific(controllers) transactions.

Each time I execute the script that runs for 1 hour, in NewRelic 1 one of the requests is missed from analytics. In the Nginx access log, I see that requests are coming to both controllers and are processed, but in NewRelic the request is not tracked.

Next execution it can appear, and all statistics will be fine. So this is not something with load testing script (as it is running, and I see in access logs it reaches the application and provides the response “200”)

What can be the possible reason for that? Any suggestions are welcome