I saw the following failure twice when running the headful system tests on a macOS 11 beta9 system:

$ gradle --continue --info -PFULL_TEST=true -PUSE_ROBOT=true :systemTests:test --tests test.javafx.scene.NewSceneSizeTest

test.javafx.scene.NewSceneSizeTest > testNewSceneSize FAILED
    java.lang.NullPointerException
        at test.javafx.scene.NewSceneSizeTest.testNewSceneSize(NewSceneSizeTest.java:137)

I only able to reproduce it twice in several attempts following the initial failure.

This is likely a test bug and not specific to macOS 11, since that test is one of a number of window-based tests that can fail in some cases if the sleep that they use isn't long enough. It also doesn't check the value of the timed wait.

We need to verify this, however.