ConcurrentModificationException in admin log

Stacktrace follows:
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at translate.AdminController.getLogAndProgress(AdminController.groovy:593)
at translate.AdminController$_closure17_closure101_closure152.doCall(AdminController.groovy:273)
at translate.AdminController$_closure17_closure101_closure152.doCall(AdminController.groovy)
at translate.AdminController$_closure12.doCall(AdminController.groovy:121)
at translate.AdminController.invokeMethod(AdminController.groovy)
at translate.AdminController$_closure17_closure101.doCall(AdminController.groovy:273)
at translate.AdminController$_closure17_closure101.call(AdminController.groovy)
at translate.AjaxRequestProcessor$_closure2.doCall(AjaxRequestProcessor.groovy:54)
at translate.AdminController$_closure17.doCall(AdminController.groovy:185)
at translate.AdminController$_closure17.doCall(AdminController.groovy)
at com.studentsonly.grails.plugins.uiperformance.CacheFilter.doFilter(CacheFilter.java:67)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)