There are 16 occurrences in the codebase (all in test code) when the result of CountDownLatch.await(timeout, TimeUnit) is not checked. It's like not checking the result of File.delete(). The common fix is to wrap CDL.await() call into assertTrue().
All 16 places could be found using the following structural search in IntelliJ:
With "CountDownLatch" type constraint on the $x$ variable.