I'm building a multimodule Java project with Maven on Bamboo 5.x, the Surefire test output for some modules seem to be interleaved after upgrading from Surefire 2.15 to Surefire 3.0.0-M5. Moreover Bamboo seems to think there are far fewer tests being run in total, although the build log is about the same length. I don't see any configuration for parallel tests, although Maven is using -T 3 in both configurations to build the entire project with multiple threads (that is, the Bamboo job uses -T 3 when it invokes mvn).
Why would upgrading Surefire 2.15 to Surefire 3.0.0-M5 suddenly cause the groups of tests in the output to be interleaved? And would this affect the number of tests Bamboo 5.x thinks has been run?