Why isn't karate-gatling logging anything with over 13 concurrent users?

Question

I have a set of Karate-Gatling performance tests. When I run them with a few concurrent users

.inject(
        constantConcurrentUsers(5)
          .during(testDuration.seconds)
      )

all works as expected - but only for a low number of concurrent users.

However as soon as I increase my concurrent users to over 14, karate-gatling stops properly logging into the simulation.log file - I only get the logs from the first few seconds, the rest of the logs are never entered. In fact, the more concurrent users I have, the sooner it happens.

What could be causing this? Some race condition that is more likely to happen with multiple users?

Happens on multiple computers, so it's probably not local config issue.