I have a Matrix job with dynamic axis that can run concurrently.

When triggering that job several times simultaneously with different axis, I often get this error message:

java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:819)
at java.util.ArrayList$Itr.next(ArrayList.java:791)
at java.util.AbstractCollection.addAll(AbstractCollection.java:333)
at java.util.LinkedHashSet.<init>(LinkedHashSet.java:169)
at com.google.common.collect.Sets.newLinkedHashSet(Sets.java:284)
at hudson.matrix.MatrixProject.rebuildConfigurations(MatrixProject.java:592)
at hudson.matrix.MatrixBuild$MatrixBuildExecution.doRun(MatrixBuild.java:345)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:584)
at hudson.model.Run.execute(Run.java:1592)
at hudson.matrix.MatrixBuild.run(MatrixBuild.java:304)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:237)
at hudson.model.OneOffExecutor.run(OneOffExecutor.java:66)

I believe that the problem is with the rebuild() method that returns a pointer to a changeable list.