We are seeing this error in console output of random builds. It happens a lot but not every time:

Email was triggered for: Success
Sending email for trigger: Success
ERROR: Could not send email as a part of the post-build publishers.
java.lang.ArrayIndexOutOfBoundsException: Assertion error: failing to load #77 DESC: lo=6,hi=2,size=13,size2=13
at jenkins.model.lazy.AbstractLazyLoadRunMap.search(AbstractLazyLoadRunMap.java:432)
at hudson.model.AbstractBuild.getPreviousBuild(AbstractBuild.java:214)
at hudson.model.AbstractProject.hasParticipant(AbstractProject.java:1564)
at hudson.model.User.getProjects(User.java:448)
at hudson.scm.MailAddressResolverImpl.findMailAddressFor(MailAddressResolverImpl.java:21)
at hudson.tasks.MailAddressResolver.resolve(MailAddressResolver.java:101)
at hudson.tasks.Mailer$UserProperty.getAddress(Mailer.java:532)
at hudson.plugins.emailext.EmailRecipientUtils.getUserConfiguredEmail(EmailRecipientUtils.java:90)
at hudson.plugins.emailext.ExtendedEmailPublisher.createMail(ExtendedEmailPublisher.java:518)
at hudson.plugins.emailext.ExtendedEmailPublisher.sendMail(ExtendedEmailPublisher.java:304)
at hudson.plugins.emailext.ExtendedEmailPublisher._perform(ExtendedEmailPublisher.java:296)
at hudson.plugins.emailext.ExtendedEmailPublisher.perform(ExtendedEmailPublisher.java:256)
at hudson.tasks.BuildStepMonitor$3.perform(BuildStepMonitor.java:36)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:820)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:792)
at hudson.model.Build$BuildExecution.cleanUp(Build.java:192)
at hudson.model.Run.execute(Run.java:1612)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:237)

Any ideas?