Cannot save a non-terminal page in the same space in a specific use case

1. Create a non-terminal page "b" in http://localhost:8080/xwiki/bin/view/Main/
2. Create another non-terminal page "B" in Main space.

Actual result:

• After you fill the name of the 2nd page and click Create, you are redirected to edit mode.
• After you save the page "B", this error is triggered:

  2016-06-29 13:45:08,317 [http://localhost:8080/xwiki/bin/preview/b/WebHome] WARN  o.h.u.JDBCExceptionReporter    - SQL Error: 1062, SQLState: 23000
  2016-06-29 13:45:08,318 [http://localhost:8080/xwiki/bin/preview/b/WebHome] ERROR o.h.u.JDBCExceptionReporter    - Duplicate entry 'b' for key 'XWS_REFERENCE'
  2016-06-29 13:45:08,407 [http://localhost:8080/xwiki/bin/preview/b/WebHome] WARN  c.x.x.w.XWikiAction            - Uncaught exception: Error number 3201 in 3: Exception while saving document xwiki:b.WebHome
  com.xpn.xwiki.XWikiException: Error number 3201 in 3: Exception while saving document xwiki:b.WebHome
          at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:669)
          at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:167)
          at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:160)
          at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1587)
          at com.xpn.xwiki.web.SaveAction.save(SaveAction.java:181)
          at com.xpn.xwiki.web.SaveAction.action(SaveAction.java:223)
          at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:431)
          at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:193)
          at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
          at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
          at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
          at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
          at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
          at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
          at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:808)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
          at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:115)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:127)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
          at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
          at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:595)
          at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
          at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
          at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
          at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
          at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
          at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
          at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:191)
          at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:72)
          at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:105)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.wysiwyg.server.filter.ConversionFilter.doFilter(ConversionFilter.java:124)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:137)
          at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
          at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
          at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
          at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
          at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
          at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
          at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
          at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
          at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
          at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
          at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
          at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
          at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
          at org.eclipse.jetty.server.Server.handle(Server.java:499)
          at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
          at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
          at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
          at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
          at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
          at java.lang.Thread.run(Unknown Source)
  Caused by: org.hibernate.HibernateException: Failed to commit or rollback transaction. Root cause []
          at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:1046)
          at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:660)
          ... 65 common frames omitted
  Caused by: org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
          at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96)
          at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
          at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275)
          at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:268)
          at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184)
          at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
          at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
          at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
          at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
          at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
          at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:1038)
          ... 66 common frames omitted
  Caused by: java.sql.BatchUpdateException: Duplicate entry 'b' for key 'XWS_REFERENCE'
          at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
          at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
          at java.lang.reflect.Constructor.newInstance(Unknown Source)
          at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
          at com.mysql.jdbc.Util.getInstance(Util.java:387)
          at com.mysql.jdbc.SQLError.createBatchUpdateException(SQLError.java:1161)
          at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1773)
          at com.mysql.jdbc.PreparedStatement.executeBatchInternal(PreparedStatement.java:1257)
          at com.mysql.jdbc.StatementImpl.executeBatch(StatementImpl.java:958)
          at org.apache.commons.dbcp2.DelegatingStatement.executeBatch(DelegatingStatement.java:345)
          at org.apache.commons.dbcp2.DelegatingStatement.executeBatch(DelegatingStatement.java:345)
          at org.apache.commons.dbcp2.DelegatingStatement.executeBatch(DelegatingStatement.java:345)
          at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
          at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
          ... 74 common frames omitted
  Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'b' for key 'XWS_REFERENCE'
          at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
          at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
          at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
          at java.lang.reflect.Constructor.newInstance(Unknown Source)
          at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
          at com.mysql.jdbc.Util.getInstance(Util.java:387)
          at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:934)
          at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
          at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
          at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
          at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
          at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
          at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
          at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
          at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:1751)
          ... 81 common frames omitted
  

• This error is generated only for non-terminal pages created in the same space and having the same name with uppercase title like an existing page with the same lowercase title.
• Issue does not reproduce for terminal pages.

PS:

• I must mention that this issue is generated by the nested spaces, since I tested the same scenario on XE 6.4.5 and I didn`t reproduced the problem there.