Some tasks in evergreen have setup that happens outside the actual test file. For instance the sharding_jscore_passthrough suite has resmoke.py set up a sharded cluster before running any actual jstests. If there is a failure setting up that cluster you see a test marked as failed, but the logs for that test have no errors in them. You have to view the full "Task Logs" and look through them to find a stack trace from resmoke.py buried in among the other output in order to know what's wrong. We should make it clear on the Task Failure page when the failure wasn't due to a test failing to run, but due to some setup failure.