ConcurrentModificationException in CDICoreBuilder when importing existing application

While working on resolving JBIDE-12690, I got the following error:

!MESSAGE Errors running builder 'CDI (Context and Dependency Injection) Builder' on project 'jboss-richfaces-webapp'.
!STACK 0
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
at java.util.HashMap$KeyIterator.next(HashMap.java:828)
at org.jboss.tools.cdi.internal.core.impl.definition.DefinitionContext.copy(DefinitionContext.java:98)
at org.jboss.tools.cdi.internal.core.impl.definition.DefinitionContext.newWorkingCopy(DefinitionContext.java:340)
at org.jboss.tools.cdi.core.CDICoreBuilder.build(CDICoreBuilder.java:199)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:728)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:239)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:292)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:295)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:351)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:374)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:143)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

This exception occurred when I imported an existing project (jboss-richfaces-webapp) that had been created in another workspace.