SaveLastReadPost. NonUniqueResultException: query did not return a unique result: 2

2015-01-26 10:17:29 [DEBUG][http-8080-44    ][kciray8][org.jtalks.jcommune.service.transactional.TransactionalPrivateMessageService] - Check permission to send private message for
 user - 18688
2015-01-26 10:17:31 [DEBUG][http-8080-36    ][vladloun][org.jtalks.jcommune.web.exception.PrettyLogExceptionResolver] - Resolving exception from handler [public org.springframewor
k.web.servlet.ModelAndView org.jtalks.jcommune.web.controller.TopicController.showTopicPage(org.springframework.web.context.request.WebRequest,java.lang.Long,java.lang.String) thr
ows org.jtalks.jcommune.plugin.api.exceptions.NotFoundException]: org.hibernate.NonUniqueResultException: query did not return a unique result: 2
2015-01-26 10:17:31 [WARN ][http-8080-36    ][vladloun][           org.jtalks.jcommune] - Handler execution resulted in exception
org.hibernate.NonUniqueResultException: query did not return a unique result: 2
        at org.hibernate.impl.AbstractQueryImpl.uniqueElement(AbstractQueryImpl.java:899)
        at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:890)
        at org.jtalks.jcommune.model.dao.hibernate.LastReadPostHibernateDao.getLastReadPost(LastReadPostHibernateDao.java:61)
        at sun.reflect.GeneratedMethodAccessor597.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
        at etm.contrib.aop.aopalliance.EtmMethodCallInterceptor.invoke(EtmMethodCallInterceptor.java:62)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
        at com.sun.proxy.$Proxy65.getLastReadPost(Unknown Source)
        at org.jtalks.jcommune.service.transactional.TransactionalLastReadPostService.saveLastReadPost(TransactionalLastReadPostService.java:222)
        at org.jtalks.jcommune.service.transactional.TransactionalLastReadPostService.markTopicPageAsRead(TransactionalLastReadPostService.java:177)
        at sun.reflect.GeneratedMethodAccessor445.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
        at org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:67)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at etm.contrib.aop.aopalliance.EtmMethodCallInterceptor.invoke(EtmMethodCallInterceptor.java:62)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
        at com.sun.proxy.$Proxy87.markTopicPageAsRead(Unknown Source)
        at org.jtalks.jcommune.web.controller.TopicController.showTopicPage(TopicController.java:239)