In each case the stack trace in the logs looks like this:
2014-10-14 20:45:24,062 TP-Processor18 ERROR sysadmin 1245x127666x2 b6hrh8 59.167.133.100,165.254.226.226 /rest/issueNav/1/issueTable [common.error.jersey.ThrowableExceptionMapper] Uncaught exception thrown by REST service: 4
java.lang.ArrayIndexOutOfBoundsException: 4
at org.apache.lucene.search.BooleanScorer2.score(BooleanScorer2.java:310)
at org.apache.lucene.search.ConjunctionScorer.score(ConjunctionScorer.java:135)
at org.apache.lucene.search.BooleanScorer2$2.score(BooleanScorer2.java:182)
at org.apache.lucene.search.BooleanScorer2.score(BooleanScorer2.java:309)
at org.apache.lucene.search.TopScoreDocCollector$InOrderTopScoreDocCollector.collect(TopScoreDocCollector.java:47)
at org.apache.lucene.search.IndexSearcher.searchWithFilter(IndexSearcher.java:572)
at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:532)
at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:391)
at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:298)
at com.atlassian.jira.index.DelegateSearcher.search(DelegateSearcher.java:177)
at com.atlassian.jira.issue.search.providers.LuceneSearchProvider.runSearch(LuceneSearchProvider.java:566)
at com.atlassian.jira.issue.search.providers.LuceneSearchProvider.getHits(LuceneSearchProvider.java:291)
at com.atlassian.jira.issue.search.providers.LuceneSearchProvider.searchAndSort(LuceneSearchProvider.java:465)
at com.atlassian.jira.issue.search.providers.LuceneSearchProvider.searchAndSort(LuceneSearchProvider.java:181)
at sun.reflect.GeneratedMethodAccessor1466.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.atlassian.plugin.osgi.hostcomponents.impl.DefaultComponentRegistrar$ContextClassLoaderSettingInvocationHandler.invoke(DefaultComponentRegistrar.java:129)
at $Proxy35.searchAndSort(Unknown Source)
at sun.reflect.GeneratedMethodAccessor1774.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:58)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.invoke(ServiceInvoker.java:62)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:131)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:119)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invokeUnprivileged(ServiceTCCLInterceptor.java:56)
at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invoke(ServiceTCCLInterceptor.java:39)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.osgi.service.importer.support.LocalBundleContextAdvice.invoke(LocalBundleContextAdvice.java:59)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:131)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:119)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy3387.searchAndSort(Unknown Source)
at com.atlassian.jira.plugin.issuenav.service.issuetable.AbstractIssueTableCreator.collectIssues(AbstractIssueTableCreator.java:166)
at com.atlassian.jira.plugin.issuenav.service.issuetable.AbstractIssueTableCreator.executeNormalSearch(AbstractIssueTableCreator.java:236)
at com.atlassian.jira.plugin.issuenav.service.issuetable.AbstractIssueTableCreator.create(AbstractIssueTableCreator.java:202)
at com.atlassian.jira.plugin.issuenav.service.issuetable.DefaultIssueTableService.createIssueTableFromCreator(DefaultIssueTableService.java:188)
at com.atlassian.jira.plugin.issuenav.service.issuetable.DefaultIssueTableService.getIssueTable(DefaultIssueTableService.java:302)
at com.atlassian.jira.plugin.issuenav.service.issuetable.DefaultIssueTableService.getIssueTableFromFilterWithJql(DefaultIssueTableService.java:124)
at com.atlassian.jira.plugin.issuenav.rest.IssueTableResource.getIssueTableHtml(IssueTableResource.java:99)
at sun.reflect.GeneratedMethodAccessor1874.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
[...]
The number after "java.lang.ArrayIndexOutOfBoundsException" varies, but it's otherwise the same. A full foreground reindex will temporarily resolve the problem, but it will reoccur within a day or so.
Workaround
Perform a full lock re-index (foreground).