Occasional testLockExpiration failures

Every now and then our build fails with the following OpenScopedLockTest.testLockExpiration test failure:

junit.framework.AssertionFailedError: A released lock must return a negative number of seconds, was: 1
at junit.framework.Assert.fail(Assert.java:47)
at junit.framework.Assert.assertTrue(Assert.java:20)
at org.apache.jackrabbit.test.api.lock.AbstractLockTest.testLockExpiration(AbstractLockTest.java:277)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at junit.framework.TestCase.runTest(TestCase.java:154)
at junit.framework.TestCase.runBare(TestCase.java:127)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:118)
at org.apache.jackrabbit.test.AbstractJCRTest.run(AbstractJCRTest.java:456)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at junit.framework.TestSuite.run(TestSuite.java:203)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at junit.framework.TestSuite.run(TestSuite.java:203)
at junit.framework.TestSuite.runTest(TestSuite.java:208)
at org.apache.jackrabbit.test.ConcurrentTestSuite.access$001(ConcurrentTestSuite.java:29)
at org.apache.jackrabbit.test.ConcurrentTestSuite$2.run(ConcurrentTestSuite.java:67)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Thread.java:595)