I spotted the following failure one time in a GHA [1] test run:

2025-08-14T12:35:27.9447862Z TaskCancelTest > cancellingA_RUNNING_TaskShouldChangeStateTo_CANCELLED() FAILED
2025-08-14T12:35:27.9449202Z org.opentest4j.AssertionFailedError: expected: <true> but was: <false>
2025-08-14T12:35:27.9450291Z at app//org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
2025-08-14T12:35:27.9451649Z at app//org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
2025-08-14T12:35:27.9452776Z at app//org.junit.jupiter.api.AssertTrue.failNotTrue(AssertTrue.java:63)
2025-08-14T12:35:27.9453675Z at app//org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:36)
2025-08-14T12:35:27.9454756Z at app//org.junit.jupiter.api.AssertTrue.assertTrue(AssertTrue.java:31)
2025-08-14T12:35:27.9455619Z at app//org.junit.jupiter.api.Assertions.assertTrue(Assertions.java:183)
2025-08-14T12:35:27.9457079Z at app//test.javafx.concurrent.TaskCancelTest.cancellingA_RUNNING_TaskShouldChangeStateTo_CANCELLED(TaskCancelTest.java:98)

We likely won't spend time on this unless / until we see this again.

[1] https://github.com/kevinrushforth/jfx25u/actions/runs/16965084943/job/48086907699